Ultrapen PT4 Free Chlorine Pen Calibration: MyronLMeters.com

Posted by 4 Apr, 2014

TweetIV. Calibration of the Ultrapen PT4 Free Chlorine Pen The manufacturer recommends calibrating twice a month, depending on usage. However, you should check the calibration whenever measurements are not as expected. For greatest accuracy, you should perform a 3-point wet pH calibration, and wet ORP calibration with the ORP Standard Solution closest in value to […]

how to calibrate free chlorine for the ultrapen pt4

how to calibrate free chlorine for the ultrapen pt4

IV. Calibration of the Ultrapen PT4 Free Chlorine Pen

The manufacturer recommends calibrating twice a month, depending on usage.

However, you should check the calibration whenever measurements are not as expected. For greatest accuracy, you should perform a 3-point wet pH calibration, and wet ORP calibration with the ORP Standard Solution closest in value to the solution you will be testing.

NOTE: If the measurement is NOT within calibration limits for any reason, “Error” will display. Check to make sure you are using a proper Myron L Company pH Buffer or ORP Standard Solution. If the solution is correct, clean the sensor as described in Sensor Cleaning section on page 4 of the operations manual. Restart calibration.

NOTE: Small bubbles trapped in the sensor may give a false calibration. After calibration is completed, measure the pH Buffer or ORP Standard Solutions again in solution check mode “SOL ck” (see pages 3 and 4 of the operations manual) to verify correct calibration.

NOTE: If at any point during calibration, you do not submerge the sensor in solution before the flashing slows, allow the PT4 to power off and start over.
NOTE: You should always calibrate with pH 7 first.

A. Calibration preparation
For maximum accuracy, fill 2 clean containers with each pH Buffer and/or ORP Standard Solution. Arrange them in such a way that you can clearly remember which is the rinse solution and which is the calibration standard/buffer. If you don’t have enough standard/ buffer, you can use 1 container of each standard/buffer for calibration and 1 container of clean water for all rinsing. Always rinse the FCE sensor between standard/buffer solutions. Ensure the FCE sensor is clean and free of debris.

B. pH Calibration using pH 7, 4, and 10 Buffer Solutions.
NOTE: You should always calibrate with pH 7 first.
1. Thoroughly rinse the PT4 by submerging the sensor in pH 7 Buffer rinse solution and swirling it around.
2. Push and release the push button to turn the PT4 on.
3. Push and hold the push button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL”, “PAr SEL”, “SOL ck”, and “ESC”.
4. Release the button when “CAL” displays.
5. The display will alternate between “PUSHnHLD” and “CAL.
6. Push and hold the button, The display will alternate between “PH” and “ORP”.
7. Release the button when “PH” is displayed.
8. The display will indicate “CAL” and the LED will flash rapidly.
9. While the LED flashes rapidly, dip the PT4 in pH 7 Buffer Calibration Solution so that the sensor is completely submerged.
10. While the LED flashes slowly, the pH calibration point will display along with “CAL”.
Swirl the PT4 around to remove bubbles, keeping the sensor submerged.
11. If the pH 7 calibration is successful, the display will indicate “SAVEd”, then “PUSHCONT” will be displayed (“PUSHCONT” will NOT be displayed if only calibrated with pH 4 or 10).
12. Push and release to continue or let the unit time out to exit after a 1-point or 2-point calibration.
13. Repeat steps 9 through 12 with pH 4 and 10 Buffer Solutions. After the 3rd calibration point is successfully saved, the display will indicate “SAVEd” and power off.
14. Verify calibration by retesting the calibration solution in solution check mode “SOL ck”, see section V below.

C. ORP Calibration using 80mV Quinhydrone, 260mV Quinhydrone, or 470mV MLC Light’s ORP Standard Solution.
NOTE: The PT4 has automatic temperature compensation in ORP calibration mode (from 15ºC to 30ºC).
1. Follow pH calibration steps 1 through 6, using ORP Solutions.
2. Release the button when “ORP” is displayed.
3. The display will indicate “CAL” and the LED will flash rapidly.
4. While the LED flashes rapidly, dip the PT4 in ORP Standard Solution so that the
sensor is completely submerged.
5. While the LED flashes slowly, the ORP calibration point will display along with “CAL”.
Swirl the PT4 around to remove any air bubbles, keeping the sensor submerged.
6. If the ORP calibration is successful, the display will indicate “CAL SAVEd”, then time out.
7. Verify calibration by retesting the calibration solution in solution check mode.

V. SOLUTION CHECK
Solution check is provided to verify the proper calibration value was recorded when using pH Buffers and ORP Standard Solutions. To verify proper calibration, simply put the PT4 into solution check mode, select the mode to verify (pH or ORP), then dip the sensor into the pH Buffer or ORP Calibration Solution so that the sensor is completely submerged and swirl around to release any air bubbles, then verify displayed value matches the value on the bottle.

To perform Solution Check:
1. Push and release the push button to turn the PT4 on.
2. Push and hold the push button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL”, “PAr SEL”, “SOL ck”, and “ESC”.
3. Release the button when “SOL ck” displays.
4. The display will alternate between “PUSHnHLD” and “SOL ck”.
5. Push and hold the button, The display will alternate between “PH” and “ORP”.
6. Release the button when desired mode (pH or ORP) is displayed.
7. While the LED flashes rapidly, dip the PT4 in FRESH buffer/calibration solution so that the sensor is completely submerged and swirl the PT4 around to remove any air bubbles.
8. Verify value displayed is correct.
NOTE: To verify ORP calibration while in solution check mode, you must manually correct for temperature variations from 25ºC. See instructions that come with the ORP Standard Solutions for temperature chart.

VI. Factory Calibration
When pH Buffers are not available, the PT4 can be returned to factory default calibration using the FAC CAL function. This will erase any stored wet calibration.
NOTE: Default factory calibration resets the electronics only and does NOT take the condition of the sensor into consideration.
To return your PT4 to factory calibration:
1. Push and release the push button.
2. Push and hold the button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL”, “PAr SEL”, “SOL ck”, and “ESC”.
3. Release the button when “FAC CAL” displays. The display will alternate between “PUSHnHLD” and “FAC CAL”.
4. Push and hold the push button. “SAVEd FAC” displays indicating the pen has been reset to its factory calibration.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT4 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Application Advice, Care and Maintenance, Product Updates, Technical Tips

Ultrapen PT4 Free Chlorine Pen Measurement: MyronLMeters.com

Posted by 4 Apr, 2014

TweetOPERATING INSTRUCTIONS Ultrapen PT4 Free Chlorine Pen NOTE: Selecting “ESC” from any menu immediately powers the PT4 off without saving changes. I. Temperature Unit Selection The PT4 allows you to select the type of units used for displaying temperature: ˚C (Degrees Celsius) or ˚F (Degrees Fahrenheit). To set the preference: 1. Push and release the push […]

how to measure free chlorine with the ultrapen pt4

how to measure free chlorine with the ultrapen pt4

OPERATING INSTRUCTIONS Ultrapen PT4 Free Chlorine Pen
NOTE: Selecting “ESC” from any menu immediately powers the PT4 off without saving changes.

I. Temperature Unit Selection
The PT4 allows you to select the type of units used for displaying temperature:
˚C (Degrees Celsius) or ˚F (Degrees Fahrenheit).
To set the preference:
1. Push and release the push button to turn the PT4 on.
2. Push and hold the button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL”, “PAr SEL”, “SOL ck”, and “ESC”.
3. Release the button while “ºCºF TEMP” is displayed. The display will alternate between “PUSHnHLD” and “ºCºF TEMP”.
4. Push and hold the button. The display will alternate between “˚C”, “˚F” and “ESC”.
Release the button when desired unit preference displays.
5. “SAVEd ºC” or “SAVEd ºF” will display; then the unit will power off.

II. FCE Mode Selection
The PT4 allows you to select the FCE measurement mode you prefer:
Hold Mode (default) — will display real-time readings until stable or 2 minutes, which ever
comes fi then display fi readings.
LIVE Mode — real-time readings are displayed continuously for up to 5 minutes, a push and release of the button will turn your PT4 off immediately.
To set the FCE measurement mode preference:
1. Push and release the push button to turn the PT4 on.
2. Push and hold the button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL”, “PAr SEL”, “SOL ck”, and “ESC”.
3. Release the button when “ModE SEL” is displayed. The display will alternate between “PUSHnHLD” and “ModE SEL”.
4. Push and hold the push button. The display will alternate between “Hold”, “LIVE” and “ESC”.
5. Release the button when desired mode displays.
6. “SAVEd” will display, then the PT4 will power off.

III. FCE Measurement
The following table explains what the LED Indicator Light signals indicate and gives the duration of each signal:

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CAUTION: To measure solution at the extremes of the specified temperature or FCE range, allow the PT4 to equilibrate by submerging the sensor in the sample solution for 1 minute prior to taking a measurement.

NOTE: If you cannot dip the PT4 in the sample solution, pour the sample into a clean container. If you don’t have a container or need to test a vertical stream of solution, use the scoop to hold sample solution.
1. Rinse the pen 3 times in a sample of the solution.
2. Push and release the push button.
3. While the LED flashes rapidly, dip the PT4 in FRESH sample solution so that the sensor is completely submerged. If you do not submerge the sensor in solution before the flashing slows, allow the PT4 to power off and retake the reading.
4. While the LED flashes slowly, swirl the PT4 around to remove any air bubbles, keeping the sensor submerged.
a. In Hold mode when the LED turns on solid, remove the PT4 from solution. The display will alternate between the final FCE and temperature readings. Note the readings for your records.
b. In LIVE mode allow the PT4 to remain in solution while the LED flashes slowly. The display will alternate between live FCE and temperature readings. Note the readings for your records. LIVE measurement will time out after 5 minutes OR push and release the push button to turn the PT4 off at any time during LIVE measurement.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT4 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Application Advice, Product Updates, Technical Tips

Ultrapen PT4 Free Chlorine Pen Features: MyronLMeters.com

Posted by 4 Apr, 2014

TweetThe Myron L ULTRAPEN™ PT4 Free Chlorine Pen is designed to be extremely accurate, fast, and simple to use in diverse water quality applications. Advanced features include automatic temperature compensation in calibration mode; highly stable microprocessor-based circuitry; user-intuitive design; and waterproof housing. A true one-handed instrument, the PT4 is easy to calibrate and easy to […]

The Myron L ULTRAPEN™ PT4 Free Chlorine Pen is designed to be extremely accurate, fast, and simple to use in diverse water quality applications. Advanced features include automatic temperature compensation in calibration mode; highly stable microprocessor-based circuitry; user-intuitive design; and waterproof housing. A true one-handed instrument, the PT4 is easy to calibrate and easy to use. To take a measurement, you simply push a button then dip the PT4 in solution. Results display in seconds.

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FEATURES
1. Push Button — turns PT4 on; selects mode and unit preferences.
2. Battery Cap — provides access to battery for replacement.
3. pocket Clip — holds PT4 to shirt pocket for secure storage.
4. Battery Indicator — indicates life remaining in battery.
5. Display — displays measurements, menu options, battery indicator, and firmware revision
(during power-up).
6. LED Indicator Light — indicates when to dip PT4 in solution, when measurement is in progress, and when to remove PT4 from solution.
7. FCE Sensor — measures Free Chlorine Equivalent of a solution.
8. Soaker Cap — contains Sensor Storage Solution to maintain sensor hydration. To remove, twist the soaker cap while pulling off using caution not to spill the Storage Solution. To replace, fill the soaker cap half full with Storage Solution. Twist the soaker cap while pushing back on, using caution, as excess Storage Solution may squirt out.
CAUTION: Do NOT push the soaker cap beyond the Cap Stop as sensor damage WILL
occur.
NOTE: The formation of KCl crystals around the soaker cap is normal. These crystals do not affect the sensor life, performance, or accuracy provided they are rinsed off with water prior to a test.
9. Scoop — used to hold sample solution when dipping is not possible. To install, push the scoop onto the sensor while shifting side-to-s
scoop off while shifting side-to-side. Verify the fully inserted into the PT4. If not, reinstall per FCE Sensor Replacement section on page 5. To use, hold the scoop directly under a vertical stream during measurement, avoiding bubbles.
10. Holster — run your belt through the strap in the back of the holster for hands-free portability.
11. Lanyard — attach through hole in top of pocket clip.
12. ORP Electrode Cleaning paper — for deep cleaning the platinum electrode.

Specifications
Free Chlorine: 0.00 – 10.00ppm
Free Chlorine Accuracy: < 5.00ppm ±0.3ppm, ≥ 5.00ppm ±0.5ppm
Free Chlorine Resolution: 0.01 ppm
Temperature Range: 0 – 71° C / 32 – 160° F
Temperature Accuracy: ± 0.1 ºC / ± 0.1 ºF
Temperature Resolution: 0.1ºC/0.1ºF
Time to Reading Stabilization: 10 – 45 seconds
Power Consumption: Active Mode 37 mA, Sleep Mode 2 μA
Temperature Compensation: Automatic In Calibration Mode From 15ºC to 30ºC
Physical Dimensions: 17.15 cm L x 1.59 cm D or 6.75 in. L x .625 in. D
Weight: 50.4 g / 1.78 oz. (without soaker cap and lanyard)
Case Material: Anodized Aircraft Aluminum with Protective Coating
Battery: One N type, Alkaline, 1.5V
Operating/Storage Temperature: 0 – 55ºC or 32 – 131ºF
Calibration Standard Solutions: pH4, pH7, pH10, ORP80, ORP260, ORP470
Enclosure Ratings: IP67 and NEMA6
EN61236-1: 2006 – Annex A: 2008: Electrostatic discharge to the PT4 may cause it to spontaneously turn on. If this occurs, the PT4 will turn off.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT4 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Product Updates, Technical Tips

Ultrapen PT3 ORP Pen Maintenance: MyronLMeters.com

Posted by 4 Apr, 2014

TweetMAINTENANCE Ultrapen PT3 ORP Pen I. Battery Replacement The PT3 display has a battery indicator that depicts the life remaining in the battery. When the indicator icon is at 3 bars, the battery is full. When the indicator icon falls to 1 bar, replace the battery with an N type battery.         […]

how to maintain and clean orp sensor for the ultrapen pt3

how to maintain and clean orp sensor for the ultrapen pt3

MAINTENANCE Ultrapen PT3 ORP Pen
I. Battery Replacement
The PT3 display has a battery indicator that depicts the life remaining in the battery. When the indicator icon is at 3 bars, the battery is full. When the indicator icon falls to 1 bar, replace the battery with an N type battery.

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1. In a CLEAN DRY environment unscrew the PT3 battery cap in a counter- clockwise motion.
2. Slide the cap and battery housing out of the PT3.
3. Remove the depleted battery out of its housing.
4. Insert a new battery into the battery housing oriented with the negative end touching the spring.
5. Align the groove along the battery housing with the guide bump inside the PT3 case and slide the battery housing back in.
6. Screw the battery cap back on to the PT3 in a clockwise direction. Do not over tighten.

II. Routine Maintenance

1. ALWAYS rinse the ORP sensor with clean water after each use.
2. ALWAYS replace the soaker cap with sponge filled with Sensor Storage
Solution to prevent the sensor from drying out after each use.
3. Cleaning the sensor: The Myron L Company recommends cleaning your sensor every two weeks, however this depends on application and frequency of use. Indications of a dirty sensor are slower and/or erroneous readings. Always recondition your sensor after cleaning.
To clean your sensor, select one of the following methods:
a. Basic Cleaning:
Using a solution made of dish soap mixed with water and a cotton swab, gently clean the inside of the sensor body and platinum electrode, rinse thoroughly with clean water, then recondition the sensor.
b. Moderate Cleaning:
Using a paste made of Comet® cleanser mixed with water and a cotton swab, gently clean the inside of the sensor body and platinum electrode, rinse thoroughly with clean water, then recondition the sensor. (If Comet® Cleanser is not available, use another mildly abrasive household cleanser).
c. Deep Cleaning:
Using ORP electrode cleaning paper and water, gently clean the platinum electrode, rinse thoroughly with clean water, then recondition the sensor.
4. Reconditioning the sensor: For greatest accuracy and speed of response, the Myron L Company recommends reconditioning the sensor after cleaning.
To recondition the sensor:
Rinse the sensor thoroughly with clean water, then allow it to soak in Storage Solution for a minimum of 1 hour (for best results allow the sensor to soak in Storage Solution overnight).
5. Do not drop, throw, or otherwise strike the PT3. This voids the warranty.
6. Do not store the PT3 in a location where the ambient temperatures exceed its specified Operating/Storage Temperature limits.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT3 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Application Advice, Care and Maintenance, Product Updates, Technical Tips

Ultrapen PT3 ORP Pen Features: MyronLMeters.com

Posted by 4 Apr, 2014

Tweet                    The ULTRAPEN™ PT3 ORP Pen is designed to be extremely accurate, fast, and simple to use in diverse water quality applications. Advanced features include highly stable microprocessor-based circuitry; automatic temperature compensation from 15ºC to 30ºC while in calibration mode; user-intuitive design; and waterproof housing. A […]

 

DH-UP-PT3-2T

 

 

 

 

 

 

 

 

 

The ULTRAPEN™ PT3 ORP Pen is designed to be extremely accurate, fast, and simple to use in diverse water quality applications. Advanced features include highly stable microprocessor-based circuitry; automatic temperature compensation from 15ºC to 30ºC while in calibration mode; user-intuitive design; and waterproof housing. A true one-handed instrument, the PT3 is easy to calibrate and easy to use. To take a measurement, you simply push a button then dip the PT3 in solution. Results display in seconds.

FEATURES
1. Push Button — turns PT3 on; selects mode and unit of measurement preferences.
2. Battery Cap — provides access to battery for replacement.
3. Pocket Clip — holds PT3 to shirt pocket for secure storage.
4. Battery Indicator — indicates life remaining in battery.
5. Display — displays measurements, menu options, battery indicator, and
firmware revision (during power-up).
6. LED Indicator Light — indicates when to dip PT3 in solution, when measurement is in progress, and when to remove PT3 from solution.
7. ORP Sensor — measures oxidation-reduction potential or redox of solution.
8. Soaker Cap — contains a sponge soaked with Sensor Storage Solution to maintain sensor hydration. To remove, twist soaker cap while pulling off. To replace, fi soaker cap with storage solution just until sponge is covered. Squeeze and release tip of soaker cap so sponge will saturate with solution, then pour out any excess solution. Twist soaker cap while pushing back on.
CAUTION: Do NOT overfill the soaker cap as solution can squirt out while you are
pushing the cap back on.
9. Scoop — used to hold sample solution when dipping is not possible. To install, push scoop onto sensor while shifting side-to-side. To remove, pull scoop off while shifting side-to-side. Verify ORP sensor r
into PT3. If not, reinstall per ORP Sen page 5. To use, pour solution into scoop or hold scoop directly under a vertical stream to collect sample.
10. Holster — feed belt through strap in back of holster for hands-free portability.
11. Lanyard — attach through hole in top of pocket clip.
12. ORP Electrode Cleaning Paper — for deep cleaning the platinum electrode.

Technical Specs

ORP Range: -1000 mV to +1000 mV
ORP Accuracy: ± 10 mV
ORP Resolution: 1 mV ORP
Temperature Range: 0 – 71° C / 32 – 160° F
Temperature Accuracy: ± 0.1 ºC / ± 0.1 ºF
Temperature Resolution: 0.1ºC/0.1ºF
Time to Reading Stabilization: 10-45 seconds
Power Consumption: Active Mode 37 mA, Sleep Mode 2 μA
Temperature Compensation: Automatic In Calibration Mode From 15ºC to 30ºC
Physical Dimensions: 17,15 cm L x 1,59 cm D or 6.75 in. L x .625 in. D
Weight: 50,4 g / 1.78 oz. (without soaker cap and lanyard)
Case Material: Anodized Aircraft Aluminum with Protective Coating
Battery: One N type, Alkaline, 1.5V
Calibration Solutions: ORP80, ORP260, ORP470
Operating/Storage Temperature: 0 – 55ºC or 32 – 131ºF
Enclosure Ratings: IP67 and NEMA6
EN61236-1: 2006 – Annex A: 2008: Electrostatic discharge to the PT3 may cause it to spontaneously turn on. If this occurs, the PT3 will turn off.

* Temperature compensation in calibration mode: Temperature affects the reaction potentials for all chemicals differently. True ORP is the direct measurement of electron activity during an oxidation-reduction reaction, regardless of temperature. However, for maximum accuracy and ease of calibration, the Myron L Company has developed three calibration solutions with known dissolved species. We derived the temperature compensation (from 15ºC to 30ºC) for those solutions, and embedded automatic temperature compensation into the calibration function of your PT3. Note: To verify calibration while in measurement mode, you must manually correct for any variation in temperature. Example: @25ºC, ORP2602OZ calibration solution will read 260mV, however @ 20.0ºC ORP2602OZ will read 265mV.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT3 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Product Updates

Measurement of Free Chlorine Disinfecting Power in a Handheld Instrument: MyronLMeters.com

Posted by 4 Sep, 2013

TweetINTRODUCTION AND OVERVIEW The most popular germicide used in water treatment is chlorine, which kills bacteria by way of its power as an oxidizing agent. Chlorine is used not only as a primary disinfectant at the beginning of the treatment process, but also at the end to establish a residual level of disinfection during distribution […]

INTRODUCTION AND OVERVIEW
The most popular germicide used in water treatment is chlorine, which kills bacteria by way of its power as an oxidizing agent. Chlorine is used not only as a primary disinfectant at the beginning of the treatment process, but also at the end to establish a residual level of disinfection during distribution as a guard against future contamination.
The most popular field test instruments and test systems for judging the level of residual chlorine, also called Free Available Chlorine (FAC), are based on colorimetric methods whereby dyeing agents are added to the sample being tested. These additives react to FAC causing a color change in the test sample. While they may detect the presence of FAC, they do not directly measure the electrochemical characteristic of FAC responsible for its disinfecting power: Oxidation-Reduction Potential (ORP). They give an incomplete and sometimes misleading picture of sanitizing strength. These methods have gained industry-wide acceptance. Unfortunately, so have the weaknesses and inaccuracies inherent to them.
The Free Chlorine Equivalent (FCE) feature avoids these pitfalls by directly measuring ORP, the germ-killing property of chlorine and other oxidizing germicides. It displays both the ORP reading (in millivolts DC) for the sample being tested as well as an equivalent free chlorine concentration in familiar ppm (parts per million). It accounts for the very significant effect of changing pH on chlorine sanitizing power; can be used for other types of oxidizing germicides and; will track the effect of additives, such as cyanuric acid, that degrade chlorine effectivity without changing the actual concentration of free available chlorine present.

CHLORINATION BASICS
NaOCl, common household bleach (5.3% NaOCl by weight) is the most popular chlorinating agent in use today. When added to water it hydrolyzes as:
NaOCl + H2O  HOCl + Na+ + OH-
Sodium hypochlorite Water Hypochlorous acid Sodium ion Hydroxide

Additionally, some of the HOCl dissociates into H+ and OCl-:
HOCl  H+ + OCl-
Hypochlorous acid hydrogen ion hypochlorite ion

Both HOCl and OCl- are oxidants and effective germicides, particularly against bacteria and viruses, with some effectivity against protozoa and endospores. HOCl is the stronger and more effective of the two species.

Chlorine Demand
When chlorine is added to water, not all of it is available to act against future contaminates. Some is deactivated by sunlight. Some is consumed by reactions with other chemicals in the water or by out-gassing as Cl2. More commonly, it is used up directly by disinfection of the pathogens already
present in the water or by combining with ammonia (NH3) and ammonium (NH4+) (byproducts of living bacteria) to form various chloramine compounds.
Chlorine Demand is the amount of chlorine in solution that is used up or inactivated after a period of time and therefore not available as a germicide.

Free Available Chlorine
Free Available Chlorine (FAC) is any residual chlorine that is available, after the chlorine demand is met, to react with new sources of bacteria or other contaminants. According to White’s Handbook of Chlorination and Alternative Disinfectants, 5th edition, this is the sum of the all of the chemical species that contain a chlorine atom in the 0 or +1 oxidation state and are not combined with ammonia or other organic nitrogen. Some species of FAC that might be present are:
• Molecular chlorine: Cl2
• Hypochlorous acid: HOCl
• Hypochlorite: OCl-
• Trichoride: Cl3- a complex formed by molecular chlorine and the chloride ions (Cl-)

In most applications the two most common species of free chlorine will be HOCl and OCl-. Much of the Cl2 will hydrolyze into HOCl that, depending on pH, will stay in the form of HOCl or partially dissociate into OCl-. Cl3- is very unstable and only trace amounts will be present. In fact, in most of the literature describing chlorination and the monitoring of chlorine residuals, free chlorine is considered to be the sum of HOCl and OCl-.

Chlorine dioxide, ClO2, is another chlorine derivative used in some public water supplies as a disinfectant. It is 10 times more soluble in water than chlorine and doesn’t hydrolyze into HOCl or dissociate into OCl-. In the absence of oxidizable substances and in the presence of hydroxyl ions, ClO2 will dissolve in water then decompose slowly forming chlorite ions (ClO2-) and chlorate ions (ClO3-), both of which are oxidants fitting White’s definition of free chlorine.

All other things being stable (temperature, pH, etc.), ORP values are related to FAC concentration levels. As the concentration of FAC in solution rises or falls, regardless of the species (HOCl, OCl-, ClO2-, ClO3- or Cl3-), the ORP value does, as well.

Combined and Total Chlorine
The term Combined Chlorine usually refers to residual chlorine that has combined with NH3 or NH4+ to form monochloramine (NH2Cl),
dichloramine (NHCl2) or trichloramine (NCl3). Combined chlorine is noteworthy here because chloramines are oxidizers and are used as germicides, though their reduction potential and therefore, disinfecting power is lower than other species of chlorine, such as HOCl, OCl- or ClO2.
Total chlorine is the sum of FAC and Combined Chlorine. An advantage of ORP-based systems is
that the aggregate ORP value of the water being tested includes the ORP levels contributed by all oxidizers, including chloramines. Therefore, ORP- based measurements automatically take into account Total Chlorine and can readily be used to judge total sanitizing strength.

Chlorine as an Oxidizing Germicide
Both HOCl and OCl- are oxidants and as such their effectivity as germicides can be determined using
ORP measurements. The cytoplasm and proteins in the cell walls of many harmful microbes are negatively charged (they have extra electrons). Any oxidant that comes into contact with the organism will gain electrons at the expense of the proteins, denaturing those proteins and killing the organism.
When enough chlorine is added to water to reach an ORP value of 650mV to 700mV, bacteria such as E. coli and Salmonella can be killed after only 30 seconds of exposure. Many yeast species and fungi can be killed with exposure of only a few minutes. Even ORP values of 350mV to 500mV indicate effective levels of chlorination with satisfactory microbe kill levels, although exposure times are required to be in the minutes rather than seconds.

The Importance of pH
pH significantly changes relative effectiveness of chlorine as a disinfectant. Different species of chlorine ions are more prevalent at different pH levels. Under typical water treatment conditions in the pH range 6–9, HOCl and OCl- are the main chlorine species. Depending on pH level, the ratio of these two free chlorine species changes.

Figure 1

Figure 1 – Distribution of Free Chlorine Species in Aqueous Solutions

Figure 1 shows that chlorine hydrolysis into HOCl is almost complete at pH ≤ 4. Dissociation of HOCl into OCl- begins around 5.5 pH and increases dramatically thereafter2. This is important because HOCl and OCl- do not have the same effectivity as disinfectants. HOCl can be 80-100% more effective as a disinfectant than OCl-. Optimum disinfection occurs at pH 5 to 6.5 where HOCl is the prevailing species of free chlorine present. As pH rises above that level, the ratio shifts towards being primarily OCl-. At pH 7.5 the ratio is about even. When the pH value rises to 8 or higher, OCl- is the dominant species. Therefore, assuming the concentration of Cl2 species is constant, the higher the pH of the solution rises above 5.5, the lower the oxidation capability and disinfecting power of the FAC.

The bottom line is knowing the concentration of FAC ions in a solution without taking pH into account can give an incomplete and sometimes incorrect picture of disinfecting power.

WHY A CHANGE IS NEEDED

The Problem with Colorimetric Testing
First and foremost, colorimetric tests only report how much chlorine is present, and as we saw in the previous section, knowing “how much” is not at all the same as knowing “how effective”.
Colorimeters and DPD kits add a reagent or several reagents to the water being tested that causes a color change representing the amount of FAC in water. In fact, they fundamentally change the chemistry of the water just to get an easy measurement.

The most obvious change is related to pH. The typical reagent/dye used in the process forces the pH of the sample to a specific level, usually 6.5 pH and thus radically alters the HOCl to OCl- ratio. If the original sample was at a pH of 7.4 to 7.6 (suggested levels for pools and spas) about 50% of the FAC present would be in the form of HOCl. At a pH of 6.5 this ratio rises to nearly 90%. While the actual concentration of FAC may be correct, a fact entirely overlooked is that the FAC in the source water includes about 40% of the much weaker sanitizing OCl-.

If that were the only change being made to the chemistry of the sample, it would be severe enough.

Figure 2 shows the result of a comparison test made using a UV spectrophotometer on two samples of water. Both were taken from a master water sample containing 5 ppm Cl2 prepared using a closed system that ensured no other oxidants or interferants were present. One was processed using a colorimeter reagent according to its operator’s manual instructions. The other was left untreated.

Figure 2

Figure 2: Chemical Alteration of Chlorinated Water by Colorimeter Additives

UV spectrophotometric analysis shows how dramatically the chemistry of the sample was changed by the addition of the colorimeter’s coloring reagent.
• The shift in the center of the spike indicates that the species of chlorine present has been altered. What was OCl- is now some other chemical species.
• The amplitude of the spike demonstrates how severely the amount of chlorine has been amplified.
• The absorption spectra where OCl- used to be is significantly depressed.

Because the area of UV absorption spectra where any OCl- would appear is so depressed, it is clear that a radical alteration is taking place above and
beyond simply changing the pH. The “ppm” value reported for the chlorine content of the water seems to be converted to a single species whose
concentration is significantly higher than the original OCl- content.

Even assuming a linear relationship between this altered chemistry and the original FAC content of the water that might be factored into the final colorimetric measurement, by completely divorcing the measurement from the pH of the source water, any direct correlation to the reduction potential of the FAC present and, therefore, real disinfecting power, is lost.

ORP = DISINFECTING POWER
What is ORP?
ORP is the acronym for Oxidation Reduction (REDOX) Potential. It is a differential measurement of the mV potentials built up between two electrodes exposed to solutions containing oxidants and/or reductants. ORP describes the net magnitude and direction of the flow of electrons between pairs of chemical species, called REDOX pairs. In REDOX reactions, one chemical of the pair loses electrons while the other chemical gains electrons. The chemicals that acquire electrons are called the oxidants (HOCl, OCl-, ClO2, bromine, hydrogen peroxide, etc.). The chemicals that give up electrons are called the reductants (Li, Mg2+, Fe2+, Cr, etc.).

Oxidants acquire electrons through the process of reduction, i.e., they are reduced. Reductants lose their electrons through the process of oxidation, i.e., they become oxidized.

How is ORP Measured?
ORP sensors are basically two electrochemical half- cells: A measurement electrode in contact with the solution being measured and a reference electrode in contact with an isolated reservoir of highly concentrated salt solution. When the solution being measured has a high concentration of oxidizers, it accepts more electrons than it looses and the measurement electrode develops a higher electrical potential than the stable potential of the reference electrode. A voltmeter in line with the two electrodes will display this difference in electrical potential (reported in mV). Once the entire system reaches equilibrium, the resulting net potential difference represents the Oxidation Reduction Potential (ORP). A positive reading indicates an oxidizing solution, and a negative reading indicates a reducing solution. More positive or negative values mean the oxidants or reductants present are stronger, they are present in higher concentrations or both.

What Does ORP Measure?
Measuring ORP is the most direct way to determine the efficacy of oxidizing disinfectants in aqueous solutions. It measures the actual chemical mechanism by which oxidizers, like chlorine, kill bacteria and viruses. The higher the ORP value, the stronger the aggregate residual oxidizing power of the solution, the more aggressively the oxidants in it will take electrons from the cells of microbes and, therefore, the more efficiently and effectively any source of new microbial contamination will be neutralized.
Also, because ORP measures the total reduction potential of a solution, ORP measures the total efficacy of all oxidizing sanitizers in solution: hypochlorous acid, hypochlorite, monochloramine, dichloramine, hypobromous acid, ozone, peracetic acid, bromochlorodimethylhydantoin, etc.

Can ORP Replace Free Chlorine Measurements?
Yes.
When correlated with known disinfection control methods, measurements and bacterial plate counts, this type of measurement gives an accurate picture of the residual chlorine sanitizing activity reported as an empirical number that is not subject to visual interpretations. Solutions with certain ORP levels kill microbes at a certain rate. Period!
ORP was first studied at Harvard University in the 1930s as a method for measuring and monitoring microbial disinfection. It has been advocated as the best way to judge residual disinfecting power of chlorinated water by water quality experts since the 1960s. ORP has long been used in bathing waters as the only means for automatic chemical dosing. The World Health Organization (WHO) suggests an initial ORP value of between 680-720 mV for safe bathing water3 and ~800 mV for safe drinking water.
For the purpose of pretreatment screening to detect chlorine levels prior to contact with chlorine- sensitive RO membranes, some manufacturers of RO membranes and other water quality treatment equipment will also specify an ORP tolerance value for prescreening and influent control.

There are, however, applications where reporting residual disinfecting power in terms of FAC concentrations is preferred and sometimes required. While ORP measurements do not directly measure the concentration of FAC, they can be correlated to free chlorine levels in ppm. Variables such as pH and temperature must be accounted for or controlled. Interfering chemicals that might be present, such as other oxidants or reductants, must also be accounted for, or better yet, removed.

Once all these factors are known or controlled, ORP values can be linked to concentrations either by way of laboratory experimentation or via mathematical formulas like the Nernst Equation, an equation that describes the relationship between the electrode potential of a specific chemical in a solution and its concentration. In either case this is an often complex and laborious process … until now.

FCE = HANDHELD ORP ACCURACY
ORP Relevance in a Handheld Instrument
The Myron L Company has developed an innovative method for using ORP-based measurement to directly monitor the disinfecting power of free chlorine and report the result in both familiar ppm units as well as straight ORP mV values.

Myron L Company’s FCE function utilizes the accurate and reliable electronic design of Myron L Company’s instruments combined with simple one- button operation to make ORP-based chlorine measurement available in an easy-to-use, handheld field instrument. Other handheld instruments may measure ORP, but only a Myron L Company instrument equipped with FCE quickly correlates ORP and pH with FAC concentration. The FCE function also includes a predictive algorithm that extrapolates a final, stable ORP value of a solution without waiting out the long response time of the typical ORP sensor.

When the FCE function is active, the instrument display alternates between the Predicative ORP reading (mV) and the Free Chlorine Equivalent (FCE) concentration (ppm). Together these features combine to make ORP-based free chlorine measurement relevant in a handheld field instrument.

FCE – How and Why it Works
The Myron L Company FCE feature cross-references ORP values with pH levels to automatically arrive at a concentration value for FAC that reflects the effect of pH on the ratio of HOCl to OCl-. This correlation is derived from a series of experiments in which exact amounts of chlorine (in the form of laboratory grade bleach: 5% NaOCl; 95% H2O) were added to deionized water in a closed system, thus controlling and excluding possible interferants. By using both a pH measurement and an ORP measurement, FCE can determine the relative contributions of HOCl and OCl- to the final ORP value and factors them into a final concentration calculation.

Figure 3

Figure 3 – Sample Experimental Data Relating FAC ppm to ORP and pH

Similar experiments were performed using water to which precise amounts of calcium chloride (CaCl2) and sodium bicarbonate (NaHCO3) were added to slightly buffer the water. This allows the FC feature to correlate low ORP values to the typically low FAC concentrations of tap water after it has been in the municipal water system for several days.

FCE – pH Included, Not Ignored
Unlike other FAC test methods that ignore the effect of pH on sanitizing power by artificially forcing the pH of their test sample to a single value, Myron L Company’s FCE includes pH in its concentration calculation. This capability gives Myron L Company’s FCE the ability to compensate for the effect of the changing ratio of chlorine species as pH
changes, resulting in a FAC concentration value germane to the actual sanitizing power of the source water. OCl- is measured as OCl-, and HOCl is measured as HOCl. Those users who are primarily concerned with or who prefer free chlorine concentration levels have a reliable measurement that gives consistent and comparable results, reading to reading, without having to rigorously control or artificially manipulate the sample’s pH.

In addition, because the FCE function displays both the FAC concentration and a predicted, stable ORP value, the user can, by comparing these two values from successive measurements, track how ORP (and disinfecting power) falls as pH rises and how ORP rises as pH is lowered when concentration is constant.

FCE – Chemistry Measured, Not Altered
Both DPD kits and colorimeters may tell the user the FAC concentration of the sample in the test tube, but since the chemistry of that sample is quite different from the source water being analyzed, the results are imprecisely related to actual disinfection power.

DPD kits and colorimeters only imply true disinfecting power; they do not measure it, and that is, after all, the whole point of the exercise.

The Myron L Company FCE method avoids these pitfalls and inaccuracies. FCE measures the real, unaltered chemistry of source water, including moment-to-moment changes in that chemistry.
The following controlled study shows exactly how differently the two methods respond, particularly at the high end where the effects of changes in pH are the greatest. In this study measurements were made with a digital colorimeter and a Myron L Company Ultrameter II 6P equipped with FCE. The solutions tested were made with various known concentrations of NaOCl in deionized water. The water was heated to above 80°C to remove any CO2 and, therefore, avoid interference from REDOX reactions between HOCL, OCl- and carbonates (HCO3).

Table 1

Table 1 – Comparison of FCE to Digital Colorimeter

In this study as the pH rises and the ratio of OCl- to HOCL rises dramatically, the FCE is able to accurately track the changing concentration of FAC. The colorimeter’s results do not.

FCE – Handheld ORP Accuracy Without the ORP Delay
One of the challenges in implementing an ORP- based free chlorine measurement in a handheld field instrument is the sometimes lengthy response time of ORP sensors. It is not uncommon for an ORP sensor to take 12 to 15 minutes to arrive at a valid stable reading. In extreme cases, such as an older sensor in poor condition and measuring a complex solution with a very low ionic strength, the ORP measurement can take up to an hour to fully stabilize. Obviously, for a handheld instrument these are unacceptably long times.

The Myron L Company FCE function includes a pioneering feature that dramatically reduces the wait for stable ORP readings. This unique feature determines an extrapolated, final, stabilized ORP reading within 1 to 2 minutes rather than the typical 15 minutes or hours for other ORP systems.

The Predictive ORP feature’s calculations are based on a model of sensor behavior developed through a series of experiments that measured the response time of a representative sample of ORP sensors over a range of controlled chlorine concentrations. The results of this set of experiments revealed that the shape of the curve is very similar for various ORP levels differing only in the initial starting point and the final stabilized reading.

Figure 4

Figure 4 – Example of ORP Sensor Response Study

Using a proprietary curve-matching algorithm, the Predictive ORP feature determines what point along the typical sensor response curve a measurement occurred and extrapolates an appropriate final reading. This extrapolated value is used to calculate the FCE ppm value without having to wait for the sensor to stabilize and is also reported directly to the instrument’s display.

FCE – FLEXIBILITY FOR THE REAL WORLD
Another advantage of an ORP-based measurement such as the Myron L Company FCE feature is that, within the limits of its range, it can be used to measure the disinfection effectivity of ANY oxidizing germicide. Myron L Company FCE measurement can be used with non-bleach oxidants, such as chloramines or even non-chlorine oxidants, such as peracetic acid, bromine or iodine.
The Predictive ORP value displayed when the FCE function is active is directly relevant for monitoring and controlling the sanitizing effectivity of oxidizing sanitizers besides HOCl and OCl-.
While the concentration values reported by the FCE function will not be absolutely correct for non-FAC oxidants, since they are based on a HOCl / OCl- model, FCE can still be an effective tool for monitoring relative changes in concentration levels. For absolute accuracy a correlative study should be performed to relate concentration levels of the oxidant in question to the ORP values displayed by the Predictive ORP feature and ppm values output by the FCE.

FCE = Effective Chloramine Control
A perfect example of the Myron L Company FCE ‘s flexibility is the use of chloramines as a germicide.
Chloramines are formed when chlorine (Cl2) and ammonia (NH3) come into contact, forming three different inorganic chemicals: monochloramine (NH2Cl), dichloramine (NHCl2) and trichloramine (NCl3). In some applications chloramines are considered an unavoidable side effect of the chlorination process; however, because they are also oxidants, there are other applications where they are used as the primary disinfectant in water treatment.

Chloramines are effective at killing bacteria and other microorganisms, but because their relative ORP levels are lower compared to HOCl or OCl- at the same concentrations, the disinfection process is slower.

Table 2

Table 2 – Electrode Potentials of Chloramines vs. HOCl

On the plus side, chloramines last longer than HOCl and OCl- (as long as 23 days in some cases), impart a less strong flavor or smell and their sanitizing
strength is not appreciably affected by changing pH.

Most importantly, chloramine-based water treatment methods produce much fewer hazardous byproducts. The US EPA limits the total concentration of the four chief hazardous byproducts of chlorination (chloroform, bromoform, bromodichloromethane, and dibromochloromethane), referred to as total trihalomethanes (TTHM), to 80 parts per billion in treated water. To avoid exceeding theses standards, many municipal water districts prefer using chloramine rather than chlorine.

The following table shows typical ORP values for various concentrations of monochloramine (NH2Cl).

Table 3

Table 3 – ORP Values for NH2Cl in Pure Water

When ORP levels of NH2Cl approach and exceed 500 mV, effective sanitization occurs with exposure times of 20 to 30 minutes. This is more than adequate for municipal water treatment.
Since Myron L Company FCE function bases its measurement on ORP, it presents an empirical, easy to interpret measurement, both in terms of the Predictive ORP display and the FAC equivalent concentration, allowing the user to monitor falling chloramine concentration as disinfection proceeds.

FCE and Cyanuric Acid (CYA) – Don’t Guess. Know!
Outdoor pool maintenance is a prime application where ORP-based chlorine measurement should be preferred. The use of chlorine to sanitize pools runs afoul of the fact that much of the chlorine added to an outdoor pool is deactivated by exposure to UV radiation in sunlight.

Cyanuric Acid (CYA) is often added to the pool water to “protect” FAC. In a typical pool at 7.6 pH about 50% of the FAC is OCl-, which reacts to UV radiation that passes through the Earth’s ozone layer (290nm). CYA combines with FAC to form N-chlorinated-cyanurates, which only react to UV radiation (215nm to 235nm) removed by the Earth’s ozone layer. Since N-chlorinated-cyanurates are also oxidizers, they also act as germicides. Unfortunately, they have much lower reduction potentials and, therefore, a much lower strength as a germicide.

Figure 5

Figure 5 – Effect of Cyanuric Acid on Chlorine ORP Values

Pool maintenance websites that advocate the use of cyanuric acid (not all of them do) often recommend levels of 40 to 80 ppm. Figure 5 shows how severely ORP and disinfecting power are affected by CYA.

The addition of only 20 ppm CYA decreases the pool water’s ORP 120 mV, reducing the effectivity of FAC from 1.5 ppm to an effectivity that is equivalent to only 0.3 ppm. Adding 40 ppm, or worse, 80 ppm, reduces sanitizing strength even more severely. This is definitely a case where more is not better.
A 1972 study on water chlorination showed that water treated with enough chlorine to kill 100% of the E. coli present in 3 minutes or less required almost 6 times as much chlorine be added for the same effect when 50 ppm of CYA was added.

Cyanuric acid beneficially affects pool chlorination by greatly reducing that portion of chlorine demand related to loss due to UV. Unfortunately, if you are using a colorimeter or DPD kit, it will tell you that your FAC concentration is unchanged and significantly misrepresent sanitizing strength
The Myron L Company FCE function’s ability to react to changes in ORP makes it an ideal tool for keeping track of how CYA affects residual sanitizing power when added to a chlorinated pool. The Predicative ORP display provides a direct and effective way to monitor changes in ORP values as CYA concentration increases. Because the FCE ppm
display reacts to changes in ORP and pH, it will reflect changes in the sanitizing strength as an “equivalent” or “effective” FAC concentration.

SUMMARY
Judging the true effectivity of chlorine as an oxidizing germicide requires more than just knowing how much chlorine is present. Changing pH or the addition of additives like cyanuric acid can radically alter the effectivity of the chlorine present. To accurately measure the effects of these issues requires a test method based on the precise measurement of ORP (the chemical characteristic directly responsible for killing microbes like bacteria and viruses) and cross-referenced to pH.

The Myron L Company FCE is the first measurement function that allows handheld, field instruments to integrate ORP and pH measurements into a system for monitoring the residual disinfecting power of free available chlorine in aqueous solutions.

• It provides an empirical measurement that does not require interpretation.
• It is not affected by water color or turbidity.
• It measures the true chemistry of the water, unaltered.
• It accounts for changes in pH.
• It reports the effects of CYA on disinfecting power.
• It can be used to monitor non-chlorine oxidants.

Myron L Meters features the Myron L FCE function in several instruments that read free chlorine – the Ultrameter II 6P, the Ultrameter III 9P, the PoolPro PS9 and PS6 models, and the
new Ultrapen PT4, soon to be released.

Categories : Science and Industry Updates, Technical Tips

pH Sensor Technical Reference: MyronLMeters.com

Posted by 3 Sep, 2013

Tweet What is pH? Definition: pH is the negative logarithm of hydrogen ion activity in a solution. The Concentration ratio of hydrogen ions (H+) and hydroxyl ions (OH-) determine the pH value of a solution. Any hydrogen activity will produce a 59.16 mV/ pH unit across the glass membrane. The measurement is expressed on a […]

pH Sensor
What is pH?

Definition: pH is the negative logarithm of hydrogen ion activity in a solution.

The Concentration ratio of hydrogen ions (H+) and hydroxyl ions (OH-) determine the pH value of a solution. Any hydrogen activity will produce a 59.16 mV/ pH unit across the glass membrane. The measurement is expressed on a scale of 0.0 to 14.0. Water with a pH of 7 is considered neutral (H+ ions = 10-7 and OH-
ions =10-7). A solution is considered acidic when the hydrogen ions (H+) exceed the hydroxyl ions (OH-), and a solution is considered an alkaline (base) when the hydroxyl ions (OH-) exceed Hydrogen ions (H+).

How is pH measured?
A pH instrument consists of three main components, refer to Figure 1.

1. The pH measuring cell: Hydrogen sensitive glass is blown onto the end of an inert glass stem.
A silver wire, treated with silver chloride (Ag/AgCl) is sealed inside the glass (cell) with a solution of potassium chloride saturated with Silver chloride.

The measuring solution has a neutral pH level of 7 or 0 mV. A properly hydrated glass sensor will produce a “Gel Layer” on the inside and outside of the glass membrane. The “Gel Layer” enables hydrogen ions to develop an electrical potential
across the pH glass sensor; a millivolt signal varies with hydrogen ion activity on the glass membrane while submerged in the solution being tested.

1. The Reference cell: A silver wire treated with silver chloride (Ag/AgCl) is sealed inside an inert glass housing (cell) with a solution of potassium chloride saturated with silver chloride. The inert glass prevents hydrogen ion activity from test solutions to influence the reference cells constant millivolt signal. The combination of the reference electrode silver- silver chloride wire, and the saturated potassium chloride solution develops a constant 199-millivolt reference signal. The millivolt signal produced inside the reference electrode does not vary as long as the chloride concentration remains constant. The reference voltage is used as a baseline to compare variations or changes in the solution being tested. The reference cell is in contact with the test solution through a reference junction that is commonly made of porous Teflon®*‚ ceramic, or a wick type material called a Pelon strip. This junction completes the measuring circuit of the pH sensor.

2. Display meter: When the pH sensor is placed in a solution, the pH-measuring cell develops a millivolt signal that reflects the hydrogen ion activity of the test solution. A high impedance meter accurately measures the small millivolt changes and displays the results in pH units on either an analog meter or digital display.

Temperature considerations:
The pH glass membrane is sensitive to the temperatures of solutions being tested. Prolonged use and/or exposure to temperatures (above 35°C) will accelerate the aging, and increase chemical attack
to the glass membrane which will shorten the overall service life of the sensor.

ELEVATED TEMPERATURES WILL SHORTEN THE SERVICE LIFE OF A pH SENSOR.

Increase temperatures also decreases the impedance of the glass membrane. The decrease of the impedance affects the millivolt output of glass membrane.
Temperature changes close to neutral (pH 7) usually do not affect pH levels; however, when levels are
< pH 3 and > pH 11 a dramatic error may occur. This problem is resolved using a built in ATC (Automatic Temperature compensation) which uses a mathematical formula (Nernst equation) to correct pH errors due to temperature factors.

Other factors that affect the life of a sensor Because standard glass electrodes are manufactured using a silver/silver chloride electrode inserted into
a potassium chloride/silver chloride solution, the following list of solutions cause the reference solution to precipitate. If the following solutions are tested, it is recommended that the pH sensor well be thoroughly rinsed. The testing of these solutions will severely reduce the service life of the pH sensor.

1. Heavy metals – silver, iron, and lead
2. Proteins
3. Low ion solutions – distilled water
4. High sodium concentrates
5. Sulfides
6. Fluorides (In high concentrations or prolonged use)

Note: This is not a complete list of solutions that can cause the reference solution to precipitate.

Sodium ion error

As solutions approach, and exceed the pH level of 12.0 the high concentration of sodium ions interfere with the standard glass membrane and cause pH levels to be displayed lower than actual pH levels. If solutions being tested are normally high alkaline, (>12 pH) a probe manufactured with special glass may be required. The special glass may be used throughout the pH range of 0 to 14, but due to the high resistance nature of the glass it will significantly increase the overall time to analyze a sample. Constant use in solutions with pH levels higher than 12 will reduce the life of the probe.

Calibration

The break down of the pH sensor electrodes and the depletion, and/or saturation of the reference solution require your pH instrument to be re-calibrated. This should normally be performed twice a month, but depending on the actual use of the instrument it may be necessary to increase the intervals between calibrations.

Refer to your operations manual or to Myron L Meters video page for detailed instructions on your specific instrument calibration procedures. The calibration should be performed using at least two pH buffer standards. The initial calibration should use Myron L pH buffer solution 7. This will check and allow the instrument to be adjusted so its output reflects 0 millivolts, neutral, or pH 7. A second calibration using a standard solution that reflects the normal range of solutions being analyzed. If acidic solutions are normally tested, a pH buffer solution 4 should be used. If solutions to be tested are normally alkaline, a pH buffer solution 10 should be used. It is not necessary to calibrate your instrument over three standards (4, 7, and 10) unless during normal daily use of the instrument, the solutions being tested varies from low to high pH ranges. In
this case an increase of calibration intervals is also recommended.

How to maximize the life of your pH or pH/ORP sensor

Myron L uses a general-purpose glass pH sensor. This glass sensor may be used in most applications. To ensure maximum life of your Myron L pH test instruments, the following information should be considered whether you are a distributor or an end user. Most premature pH sensor failures can be prevented with a few maintenance procedures. The following procedures should be performed after using your Myron L meter, or if you plan to store your meter for an extended period of time.

1. The pH sensor well (fig 1) must be filled with
Myron L storage solution (preferred) or Myron L pH buffer 4, or tap water with table salt added and its protective cap (with foam insert) firmly installed.
Failure to do so will:
• Allow the glass membrane to dry out. A de- hydrated glass membrane will not produce the necessary “Gel layer” on the sensor surface, which is essential to allow the exchange of hydrogen ions (measure pH).
• Allow airborne contaminants to settle on the glass membrane surface. Once contaminants dry onto the surface of the glass membrane, it will inhibit the transfer of hydrogen ions. (See factory approved cleaning process below.)
• Allow the reference junction to dry out. The reference junction material is usually a wick or fiber type material that completes the electrical circuit between the reference electrode cell
and the solution being tested. Dehydration causes the reference solution to leach out of the electrode cavity, and form crystals in the junction. This is normally referred to as the “Bridging effect”.
Repeated dehydration of the pH or pH/ORP sensor will cause the instrument to have a slower response time, and be more difficult to calibrate. Dehydration will
significantly reduce the normal service life of the sensor.

2. Store spare pH or pH/ORP sensors in a refrigerator. “Do not Freeze”. Take proper precautions not to allow the temperature to fall below freezing. This
will cause the solution to expand and may damage the electrodes inside the sensor. Storage in a refrigerated environment will slow the evaporation of the storage solution, but not prevent evaporation. Always inspect and replace storage solution in spare sensor well on a regular basis.
Note: When using the Myron L storage solution, it is common for white crystal formations to form around the seal of the pH sensor well and protective cap; this is a normal occurrence as the solution evaporates. Never store the sensor in high purity water (distilled or de-ionized).
Approved factory cleaning process

Figure 1

Failure to do so will:
• Allow the glass membrane to dry out. A de- hydrated glass membrane will not produce the necessary “Gel layer” on the sensor surface, which is essential to allow the exchange of hydrogen ions (measure pH).
• Allow airborne contaminants to settle on the glass membrane surface. Once contaminants dry onto the surface of the glass membrane, it will inhibit the transfer of hydrogen ions. (See factory approved cleaning process below.)
• Allow the reference junction to dry out. The reference junction material is usually a wick or fiber type material that completes the electrical circuit between the reference electrode cell
and the solution being tested. Dehydration causes the reference solution to leach out of the electrode cavity, and form crystals in the junction. This is normally referred to as the “Bridging effect”.
Repeated dehydration of the pH or pH/ORP sensor will cause the instrument to have a slower response time, and be more difficult to calibrate. Dehydration will
significantly reduce the normal service life of the sensor.

2. Store spare pH or pH/ORP sensors in a refrigerator. “Do not Freeze”. Take proper precautions not to allow the temperature to fall below freezing. This
will cause the solution to expand and may damage the electrodes inside the sensor. Storage in a refrigerated environment will slow the evaporation of the storage solution, but not prevent evaporation. Always inspect and replace storage solution in spare sensor well on a regular basis.
Note: When using the Myron L storage solution, it is common for white crystal formations to form around the seal of the pH sensor well and protective cap; this is a normal occurrence as the solution evaporates. Never store the sensor in high purity water (distilled or de-ionized).

Approved factory cleaning process for the pH sensor
During normal use of your Myron L handheld pH or pH/ORP meter, you’ll have to clean your pH sensor bulb. The cleaning is necessary because of deposits left on the sensor from the test samples.
If you suspect your instrument is inaccurate, or the display value drifts, or the response is slow and sluggish, try the following.
Rinse the sensor well (three times) and fill with pH buffer 4 solution. If the pH continues to drift below the pH 4 level (i.e. 3, 2, or 1) repeat the test using pH buffer 10. If the pH level drifts beyond the pH level of 10 (i.e. 11, 12 etc.) follow the cleaning procedure outlined below.
If the pH levels of the buffer solutions 4 and 10 actually drift towards pH 7, this could mean that the pH sensor is damaged and needs to be replaced.

Caution: Wear proper eye protection and gloves during the cleaning procedure.

The following procedures may help clean and recover the pH or pH/ORP sensors.

NOTE: Not all pH or pH/ORP sensors can be recovered.
1. Fill the pH/ORP sensor well with 100% Isopropyl alcohol. If not available use additive- free rubbing alcohol (70%). This will remove any oils.
2. Allow the sensor to soak for 10 minutes.
3. Rinse with RO or DI water.
4. Rinse the sensor well (three times) and fill
with Myron L storage solution or Myron L pH buffer 4. Replace the protective cap and allow the sensor to recover overnight.
5. Re-calibrate the instrument according to the Myron L instruction manual that was provided with your instrument. If the instrument fails to calibrate properly, continue to the next step.

If the above procedure does not recover the pH sensor function, perform the following:
1. Fill the pH or pH/ORP sensor well with a hot salt solution 60°C (140°F) potassium chloride (KCI preferred) or hot tap water with table salt (NaCl). Allow the solution to cool.
2. Re-calibrate the instrument according to the Myron L instruction manual that was provided with your instrument. If the instrument fails to calibrate properly, the pH or pH/ORP sensor must be replaced.

Warranty
The manufacturer warrants the pH and pH/ORP sensor assemblies against manufacturer defects. Shelf life for most pH and ORP sensors is 12 months. Failure to maintain proper hydration of the glass pH sensors or the use of the instrument in any manner not described in the operation manual supplied with the instrument may shorten the life of the sensor.
*CAUTION: If you do not use your Myron L instrument on a regular basis or if you are a stocking distributor, the storage solution in the pH or pH/ORP sensor well will evaporate over time and must be replenished. To prevent premature pH glass sensor failure, the manufacturer suggests a preventative maintenance program. Failure to do so could void the factory warranty. The use of liquids containing high levels of solvents, such as acetone, xylene, and chlorinated hydrocarbons, or other harsh chemicals in your Myron L meter is not recommended. Doing so may damage the sensor.

Categories : Care and Maintenance, Technical Tips

Ultrapen PT1 – Product Overview Video

Posted by 21 Apr, 2013

TweetLearn about the Myron L Company Ultrapen PT1. In this video, we will give an overview of the Ultrapen PT1 instrument and its functions. The Ultrapen PT1 package includes: – the PT1 Pocket Tester Pen with battery installed – Measurement Scoop – Pocket Clip – Holster – Lanyard – and Operating Instructions The Ultrapen PT1 […]

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Learn about the Myron L Company Ultrapen PT1.

In this video, we will give an overview of the Ultrapen PT1 instrument and its functions.

The Ultrapen PT1 package includes:

- the PT1 Pocket Tester Pen with battery installed
- Measurement Scoop
- Pocket Clip
- Holster
- Lanyard
- and Operating Instructions

The Ultrapen PT1 has 5 different modes of measurement. These include:

- Cond KCl mode, which measures Conductivity for potassium chloride solutions, the measurement is displayed as microsiemens (μS). This is the standard mode for most conductivity applications.

- TDS 442 mode, which measures Total Dissolved Solids for Natural Water solutions, the measurement is displayed as parts per million (ppm).

- TDS NaCl mode, which measures TDS for sodium chloride solutions, the measurement is displayed as ppm.

- SALT 442 mode, which measures Salinity for Natural Water solutions, the measurement is displayed as parts per thousand (ppt).

- SALT NaCl mode, which measures Salinity for sodium chloride solutions, the measurement is displayed as parts per thousand (ppt)

A few other specifications we’d like to highlight are the Durable, Fully Encapsulated waterproof Electronics with Automatic Temperature Compensation and Autoranging measurements. The instrument casing is made out of anodized aluminum, so it can withstand harsh environments.

- The PT1 has an Accuracy of ±1% of READING designed to give Reliable Repeatable Results.

-The PT1 also has a measuremante range of 1 – 9,999 for Conductivity, TDS, and Salinity. with a temperature range of 32 – 160 degrees F

With all of the different functions and durable design, this small pen can handle a variety of applications. Now that you are a bit more familiar with the PT1, we will demonstrate how to use its various functions.

All the functions of the PT1 are activated by pressing the button on the end.

If you press the button and release, it will turn on and prepare to take a reading in the last mode that you used.

The screen will display the software version, then the Measurement mode, then the red light will begin blinking rapidly, this is when you will need to submerge the pen to get the measurement. Wehn the light blinking slows, this is when the pen is measuring the solution. When the red light stays red, the measurement is complete and will display on the screen.

To switch modes, press and release the button to turn it on, then simply press and hold the button to cycle through the different menu options. As the options change, just release the button to select that menu option. The screen will ask you to ‘Push and Hold’ the button to confirm your choice. If there are sub-menu options (such as choosing the Solution Selection menu), then as you hold the button, it will continue to cycle through those sub-menu options. Again, you simply release the button to choose one. Then push and hold to confirm. the PT1 will show ‘SAVED’ on the display.

These are the different menu options:

- Calibration mode (shown as CAL)

- Solution selection mode (shown as SOL SEL)

- Factory calibration mode (shown as FAC CAL)

- Temperature selection mode (shown as C* F* temp)

- Escape mode for exiting the menu (shown as ESC)

To calibrate the Ultrapen PT1, attach the measurement scoop to the end of teh pen. Then rinse it three times with your calibtaion solution.

Start the calibration by pressing and releasing the button to turn it on, then simply press and hold the button to cycle through the different menu options. Release the button when ‘CAL’ is shown. When the red light starts blinking rapidly, pour the calibration soution into the scoop and wait. The pen will read teh solution and automatically adjust the calibration settings based on teh reading. This assumes you are using calibration solution that is not contaminted or expired and that your scoop and measuremetn cell is clean.

A quick tip when using theinstrument:

- When submerging the pen for measurements, make sure there are not bubbles trapped on the cell epectrodes by tapping it to knock them free.

If you have more questions about this instrument, please submit them in the reviews section on the product details page at MyronLMeters.com.

Categories : Videos

Myron L Meters Thanks Pentair!

Posted by 11 Apr, 2012

Tweet Pentair is a global diversified industrial company headquartered in Minneapolis, Minnesota. Its Water Group is a global leader in providing innovative products and systems used worldwide in the movement, treatment, storage and enjoyment of water. Pentair’s Technical Products Group is a leader in the global enclosures and thermal management markets, designing and manufacturing thermal […]

Pentair is a global diversified industrial company headquartered in Minneapolis, Minnesota. Its Water Group is a global leader in providing innovative products and systems used worldwide in the movement, treatment, storage and enjoyment of water. Pentair’s Technical Products Group is a leader in the global enclosures and thermal management markets, designing and manufacturing thermal management products and standard, modified, and custom enclosures that protect sensitive electronics and the people who use them. With revenues of about $3 billion, Pentair employs approximately 14,500 people worldwide.

Pentair’s Residential Flow Global Business Unit is a leading provider of residential water pumps, irrigation and crop spray equipment, and marine and specialty pumps and accessories. Key markets include residential end users, waste water dealers and distributors, and agricultural irrigation, and crop protection industries. It also provides specialty application water management products for recreational vehicles (RV), marine, and mobile fire markets. Residential Flow brands include STA-RITE®, Myers®, Hydromatic®, Flotec®, BERKELEY®, AERMOTOR™, Simer®, Hypro®, FoamPro®, SHURflo®, Onga™, Nocchi™ and Jung Pumpen®.

Pentair’s Residential Filtration Global Business Unit provides clean, safe, refreshing water to families around the world by using innovative, environmentally-focused, and energy-saving technologies and solutions. The business addresses consumer markets with a range of filtration, softener, and deionization products and systems.    Pentair Residential Filtration brands include Fleck®, Autotrol, Structural™, Aquamatic, PENTEK®, SIATA®, WellMate®, American Plumber®, GE, OMNIFILTER® and Fibredyne™.

Pentair’s Filtration Solutions Global Business Unit is a leading component and equipment provider in the global marketplace for treating air, gas, water and other fluids and water and fluid filtration and separation. The business serves a variety of markets, including commercial, industrial, hospitality, healthcare, and energy. Products range from pressure vessels, to filtration systems, various filtration media, and separation technologies and related components. Pentair Filtration Solutions brands include Everpure®, SHURflo®, CodeLine® and Porous Media™.

Pentair’s Engineered Flow Global Business Unit is a global leader in mid-to-large fluid management products and applications. The business delivers a range of products from the world’s largest flood control pumps to sophisticated fire and HVAC pumps and products in the municipal, industrial, and commercial markets. Pentair Engineered Flow brands include Myers, Aurora®, Hydromatic, Fairbanks Morse™, and Delta Environmental™.

Pentair Water Pool and Spa® Global Business Unit is a global leader in swimming pool and spa and aquatic equipment. The business has built a reputation as an innovation leader, providing high performance, reliable and energy-efficient filters, controls, sanitizers, pumps, heaters, cleaners, and accessory products for residential and commercial pool owners and operators. Pentair Pool & Spa® brands include Pentair Pool Products® and Sta-Rite®.

Pentair’s Technical Products Global Business Unit is a leading provider of product and service solutions for enclosing, protecting, and cooling electrical and electronic systems. Its industry-leading brands provide a broad variety of standard, modified and engineered solutions to the commercial, communications, energy, electronics, industrial, infrastructure, medical, and security and defense markets.  Pentair Technical Product brands include Hoffman®, Schroff®, McLean Cooling Technology® Aspen Motion Technologies™, CALMARK®, Birtcher®, and Taunus™.

We pride ourselves on having a “Win Right” attitude and we look to our leaders to uphold Pentair’s values

Myron L Meters is proud to do business with Pentair.

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