Water Quality Parameters: MyronLMeters.com

Posted by 15 Apr, 2014

TweetWater Quality Parameters Measuring Key Water Quality Parameters The right meter is essential for measuring any of several key water quality parameters: Conductivity is the ability of water to conduct an electrical current and is an indirect measure of the conductive ionic mineral concentration. The more conductive ions that are present, the more electricity can be […]

Water Quality Parameters

Measuring Key Water Quality Parameters

The right meter is essential for measuring any of several key water quality parameters:

Conductivity is the ability of water to conduct an electrical current and is an indirect measure of the conductive ionic mineral concentration. The more conductive ions that are present, the more electricity can be conducted by the water. This measurement is expressed in microsiemens per centimeter (µS/cm) at 25º Celsius. Myron L Meters carries a complete line of conductivity meters, including the Ultrameter II 4P.

Resistivity is the inverse of conductivity. Electrical conductivity is a measure of water’s resistance to an electric current. Water itself has a weak electrical conductivity. Electric current is transported in water by dissolved ions, making conductivity measurement a quick and reliable way to monitor the total amount of ionic contaminants in water. Myron L Meters carries a complete line of resistivity meters, including inline monitor/controllers like the 753II Resistivity Digital Monitor/Controller. Read more about Measuring Key Water Quality Parameters

The Ultrameter III 9P is the most comprehensive water meter on the market, measuring 9 parameters with a single instrument: Conductivity, Resistivity, TDS, Alkalinity, Hardness, Langelier Saturation Index,
ORP/Free Chlorine, pH, Temperature. Three parameters – LSI, hardness, and alkalinity require titration. Find out more about the Ultrameter III 9P

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Water Quality Parameters: MyronLMeters.com was originally published on Myron L Meters Blog

Categories : Uncategorized

Measuring Key Water Quality Parameters: MyronLMeters.com

Posted by 12 Apr, 2014

TweetThe right meter is essential for measuring any of several key water quality parameters:Conductivity is the ability of water to conduct an electrical current and is an indirect measure of the conductive ionic mineral concentration. The more conductive ions that are present, the more electricity can be conducted by the water. This measurement is expressed […]

The right meter is essential for measuring any of several key water quality parameters:

Conductivity is the ability of water to conduct an electrical current and is an indirect measure of the conductive ionic mineral concentration. The more conductive ions that are present, the more electricity can be conducted by the water. This measurement is expressed in microsiemens per centimeter (µS/cm) at 25º Celsius. Myron L Meters carries a complete line of conductivity meters, including the Ultrameter II 4P.

Resistivity is the inverse of conductivity. Electrical conductivity is a measure of water’s resistance to an electric current. Water itself has a weak electrical conductivity. Electric current is transported in water by dissolved ions, making conductivity measurement a quick and reliable way to monitor the total amount of ionic contaminants in water. Myron L Meters carries a complete line of resistivity meters, including inline monitor/controllers like the 753II Resistivity Digital Monitor/Controller.

Total Dissolved Solids (TDS) is also a measurement of the amount of dissolved minerals in the water. In this instance they would be called solids in solution. The quantity of dissolved solids in the solution is directly proportional to the conductivity. In this case, conductivity is the measurement but it is used to estimate TDS. It is measured with a conductivity meter but is reported as TDS in parts per million (ppm), via a complex algorithm. Myron L Meters carries a complete line of TDS meters, including the Ultrapen PT1.

pH is a measure of the concentration of hydrogen ions in the water, indicating the acidity or alkalinity of the water. On the pH scale of 0-14, a reading of 7 is considered to be neutral. Readings below 7 indicate acidic conditions, while readings above 7 indicate the water is alkaline or basic. Naturally occurring fresh waters have a pH range between 6 and 8. Myron L Meters carries a complete line of pH meters, including the Ultrapen PT2

Temperature is expressed in degrees Celsius (C) or Fahrenheit (F). Most digital handheld Myron L Meters include a temperature function.



Oxidation reduction potential (ORP)can correlate millivolt readings to the sanitization strength of the water. Microbes can cause corrosion, fouling, and disease, and oxidizing biocides are usually used to keep microbial levels under control. ORP is expressed in millivolts (mV). Myron L Meters carries a complete line of ORP meters, including the Ultrapen PT3

Free Chlorine refers to both hypochlorous acid (HOCl) and the hypochlorite (OCl–) ion or bleach, and is commonly added to water systems for disinfection. Free chlorine is typically measured in drinking water disinfection systems to find whether the water system contains enough disinfectant.  Myron L Meters Ultrameter II 6PFCe and Ultrapen PT4 can both be used to measure free chlorine.

Salinity is simply a measure of the amount of salts dissolved in water, a measurement useful to pool service technicians and others.  You can measure salinity with a Myron L Pool Pro PS6.

Alkalinity is a measure of the capacity of water or any solution to neutralize or “buffer” acids. This measure of acid-neutralizing capacity is important in figuring out how “buffered” the water is against sudden changes in pH. Alkalinity is a titration function of the Ultrameter III 9PTKA.

Hardness is caused by compounds of calcium and magnesium, and by a variety of other metals.  As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. Calcium and magnesium dissolved in water are the two most common minerals that make water “hard.” Hardness is a titration function of the Ultrameter III 9PTKA.

LSI or Langelier Saturation Index helps you determine the scaling potential of water. LSI is a calculated number used to predict the calcium carbonate stability of water. It indicates whether the water will precipitate, dissolve, or be in equilibrium with calcium carbonate. LSI is a titration function of the Ultrameter III 9PTKA.

MyronLMeters.com is the premier internet retailer of accurate, reliable Myron L meters.  Save 10% when you order Myron L meters online at MyronLMeters.com. You’ll find reliable instruments for every water quality parameter mentioned above.



 

 

 

Categories : Uncategorized

Ultrapen PT1 Conductivity, TDS and Salinity Calibration: Myron L Meters

Posted by 3 Apr, 2014

TweetThe Ultrapen PT1 is designed to be very reliable and requires only infrequent calibration. The factory recommends calibrating each measurement mode you use once monthly. However, you should check the calibration whenever measurements are not as expected. The PT1 is programmed for 2 calibration options: Wet Calibration or Factory Calibration. Wet calibration is most accurate. […]

The Ultrapen PT1 is designed to be very reliable and requires only infrequent calibration. The factory recommends calibrating each measurement mode you use once monthly. However, you should check the calibration whenever measurements are not as expected. The PT1 is programmed for 2 calibration options: Wet Calibration or Factory Calibration. Wet calibration is most accurate. But if a high quality standard KCl-1800 µS or 442-3000 ppm solution is not available, the PT1 can be returned to factory settings.

A. Wet Calibration
Use calibration solution specified for measurement mode: Use KCL- 1800 for Cond KCl; Use 442-3000 for tdS 442, SALt 442, tdS NaCl, and SALt NaCl. See Specifications table for 442 solution ppm NaCl equivalent value. Calibrating TDS simultaneously calibrates SALT for the same value and vice versa.
1. Pour calibration solution into a clean container.
2. Rinse the pen 3 times by submerging the cell in fresh calibration solution and swirling it around.
3. Remove pen from solution, then fill the container one more time.
4. Press and release the push button. The LCD will briefly display the firmware version then the current measurement mode. Ensure the PT1 is in the correct solution mode.
5. Immediately push and hold the push button. The display will scroll through “CAL”, “SOL SEL”, “FAC CAL”, “ºCºF TEMP”, and “ESC”. Release the button when “CAL” displays.
6. Grasp the pen by its case with your fingers positioned between the
display and the pen cap to avoid sample contamination.
7. While the LED flashes rapidly, dip the pen in calibration solution so that the cell is completely submerged. If you do not submerge the cell in solution before the fl slows, allow the pen to power off and start over.
8. While the LED flashes slowly, swirl the pen around to remove bubbles, keeping the cell submerged. Keep pen at least 1 inch (2½ cm) away from sides/bottom of container.
9. When the LED light stays on solid, remove the pen from the solution. “CAL SAVED” will display indicating a successful calibration.
Note: If an incorrect solution is used or the measurement is NOT within calibration limits for any other reason, “Error” displays alternately with “CLEAn CEL/CHEC SOL”. Check to make sure you are using the correct calibration solution. If the solution is correct, clean the cell by submerging the cell in a 1:1 solution of Lime-A-Way® and water for 5 minutes. Rinse the cell and start over.
10. Small bubbles trapped in the cell can give a false calibration. Measure the calibration solution again to verify correct calibration. If the reading is not within ±1% of the calibration solution value, repeat calibration.

B. Factory Calibration
If you do not have the proper calibration solution or wish to restore the pen to its original factory settings for any other reason, use the FAC CAL function to calibrate the PT1.
1. Press and release the push button. The LCD will briefly display the firmware version then the current measurement mode.
2. Immediately push and hold the push button. The display will scroll through “CAL”, “SOL SEL”, “FAC CAL”, “ºCºF TEMP”, and “ESC”. Release the button when “FAC CAL” displays.
3. While the display scrolls through “PUSHnHLD” and “FAC CAL”, push and hold the push button until the display scrolls through “SAVEd” and “FAC CAL”, indicating the pen has been reset to its factory calibration.
4. Allow the pen to time out to turn power off.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT1 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Product Updates

Ultrapen PT1 Conductivity, TDS and Salinity Pen Measurement: MyronLMeters.com

Posted by 3 Apr, 2014

TweetI. solution selection The PT1 allows you to select from several preprogrammed measurement modes. The following table lists measurement modes with their corresponding parameters; temperature compensation and TDS conversion solution models; and units of measure. Mode Parameter solution Model units Cond KCl Conductivity potassium chloride microsiemens (µS) tds 442 Total Dissolved Solids (TDS) 442™ Myron L […]

I. solution selection

The PT1 allows you to select from several preprogrammed measurement modes. The following table lists measurement modes with their corresponding parameters; temperature compensation and TDS conversion solution models; and units of measure.

Mode Parameter solution Model units
Cond KCl Conductivity potassium chloride microsiemens (µS)
tds 442 Total Dissolved Solids (TDS) 442™ Myron L NaturalWater Standard parts per million (ppm)
tds NaCl TDS sodium chloride ppm
salt 442 Salinity 442™ Myron L NaturalWater Standard parts per thousand (ppt)
salt NaCl Salinity sodium chloride ppt

 

esc This is the escape function. Selecting escape exits solution selection without saving changes and turns the PT1 off.

 

To select a measurement mode:
1. Press and release the push button. The LCD will briefly display the firmware version then the current measurement mode. If the measurement parameter and solution type displayed are correct, proceed to Temperature Unit Selection.

If not, proceed to step 2.

2. Immediately push and hold the push button. The display will scroll through “CAL”, “SOL SEL”, “FAC CAL”, “ºCºF TEMP”, and “ESC”. Release the button when “SOL SEL” displays.

3. While the display scrolls through “PUSHnHLD” and “SOL SEL”, push and hold the push button. The display will scroll through “Cond KCl”, “tdS 442”, “tdS NaCl”, “SALt 442”, “SALt NaCl” and “ESC”. Release when the desired measurement mode displays.

4. “SAVED” displays indicating the measurement mode is saved in memory. Allow the pen to time out to turn power off.

II. Temperature Unit Selection

The PT1 allows you to select the type of units used for temperature measurements. The following table lists preference options with their corresponding units.

Mode Unit Preference

C Degrees Celsius

F Degrees Fahrenheit

esc This is the escape function. Selecting escape exits temperature unit selection without saving changes and turns the PT1 off.

To set the preference:
1. Press and release the push button. The LCD will briefly display the firmware version then the current measurement mode.
2. Immediately push and hold the push button. The display will scroll through “CAL”, “SOL SEL”, “FAC CAL”, “ºCºF TEMP”, and “ESC”. Release the button when “ºCºF TEMP” displays.
3. While the display scrolls through “PUSHnHLD” and “ºCºF TEMP”, push and hold the push button. The display will scroll through “C”, “F” and “ESC”. Release when the desired unit option displays.
4. “SAVED” displays indicating the unit preference is saved in memory.
Allow the pen to time out to turn power off.

III. Normal Operation

Before you take a reading, make sure the pen is clean, calibrated and in the appropriate measurement mode. The sample solution must also be within the specified measurement range. Keep all foreign material away from the sample to avoid contamination.

Note: If you cannot dip the pen in the sample solution, pour the sample into a clean container. If you don’t have a sample container and need to test a vertical stream of solution, use the scoop.

The following table explains what the LED Indicator Light signals mean and gives the duration of each signal.

LED Indicator Light Signal Meaning duration

Rapid Flashing Dip pen in solution 6 sec

Slow Flashing Measurement in process 10-20 sec

Solid Light Note measurement value 6 sec

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

1. Rinse the pen 3 times by submerging the cell in fresh sample solution and swirling it around.

2. Remove pen from solution, then press and release the push button. Firmware version will be displayed, then current measurement mode.

3. Grasp the pen by its case with your fingers positioned between the display and the pen cap to avoid sample contamination.

4. While the LED flashes rapidly, dip the pen in fresh sample solution so that the cell is completely submerged. If you do not submerge the cell in solution before the flashing slows, allow the pen to power off and retake the reading.

5. While the LED flashes slowly, swirl the pen around to remove bubbles, keeping the cell submerged. Keep the pen at least 1 inch (2½ cm) away from sides/bottom of container, if applicable.

6. When the LED turns on solid, remove the pen from solution. The display will alternate between the measurement and temperature readings. Note the readings for your records.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT1 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Product Updates

Ultrapen PT1 Conductivity, TDS, Salinity Pen Features: MyronLMeters.com

Posted by 3 Apr, 2014

TweetThe ULTRAPEN™ PT1 Conductivity/ TDS/Salinity Pen is designed to be extremely accurate, fast and simple to use in diverse water quality applications. Advanced features include the ability to select from 3 different solution types that model the characteristics of the most commonly encountered types of water; proprietary temperature compensation and TDS conversion algorithms; highly stable […]

The ULTRAPEN™ PT1 Conductivity/ TDS/Salinity Pen is designed to be extremely accurate, fast and simple to use in diverse water quality applications. Advanced features include the ability to select from 3 different solution types that model the characteristics of the most commonly encountered types of water; proprietary temperature compensation and TDS conversion algorithms; highly stable microprocessor-based circuitry; user-intuitive design; and waterproof housing. A true one-handed instrument, the PT1 is easy to calibrate and easy to use. To take a measurement, you simply press a button then dip the pen in solution. Results display in seconds.

Features
1. Push Button — turns instrument on; selects mode and unit preferences.
2. Pen Cap — provides access to battery for replacement.
3. Clip — holds pen to shirt pocket for secure storage.
4. Battery Indicator — indicates charge left in battery.
5. display — displays measurements, mode options and battery indicator.
6. LED Indicator Light — indicates when to dip instrument in solution, when measurement is in progress, and when to remove instrument from solution.
7. electrodes — measure electric current of solution.
8. Cell — contains flux field in defined area for accurate current
measurement.
9. scoop — contains sample solution for measurement when sampling from a vertical stream. To use, slide the open end of the scoop over the bottom of the pen until the neck of the scoop is flush with the top of the cell. Hold pen with scoop end under stream. Rinse and fill with sample solution 3 times. Fill with solution again, then take measurement. We recommend you recalibrate the pen using the scoop to retain accuracy of ±1%.

Technical Specs

Measurement Range: 1 – 9999 µS or ppm (0.0010 – 9.999 ppt salinity)
Accuracy (After Wet Calibration): ± 1% of reading
Repeatability: < 1000 µS or ppm ± 1 Count
≥ 1000 µS or ppm ± 0.3% of reading
Resolution: Conductivity and TDS:
0.1 for 1.0 – 99.9 µS or ppm
1 for 100 – 9999 µS or ppm
Salinity: 0.0001 for 0.0010 – 0.0999 ppt
0.001 for 0.100 – 9.999 ppt
Temperature: 0.1 ºC or ºF
Time to Reading Stabilization: 10 – 20 seconds
Active Mode Power Consumption: 30 – 100 mA
Sleep Mode Power Consumption: 2 µA
Temperature Measurement Range: 0 – 71° C or 32 – 160° F
Temperature Accuracy Displayed: ± 0.1 ºC or ± 0.1 ºF
Temperature Compensation Method: Automatic to 25ºC
Physical Dimensions: 17.15 cm L x 1.59 cm D or 6.75 in. L x .625 in. D
Weight: 55 g or 1.94 oz.
Case Material: Anodized Aluminum with Protective Coating
Battery Type: N type, Alkaline
Battery Voltage: 1.5 V
Calibration Solution Point: 1800 µS KCl; 3000 ppm 442™ (2027 ppm NaCl)
Operating/Storage Temperature: 0 – 55ºC or 32 – 131ºF
Water Resistance: IP67 and NEMA 6

Electrostatic discharge to case of instrument may cause PT1 to spontaneously power on. In this case, the PT1 will power off after several seconds.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT1 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Product Updates

TDS Calibration on the Ultrameter II 6PIIFCe: MyronLMeters.com

Posted by 23 Mar, 2014

Tweet  *Note: This procedure applies to the Ultrameter, PoolPro, TechPro, and D-6 Dialysate meter. a. Fill and rinse the conductivity cell three times with a 442 standard solution. In this example, we’re using 442-3000. b. Refill conductivity cell with same standard solution you rinsed with. c. Press           then press   […]

 

*Note: This procedure applies to the Ultrameter, PoolPro, TechPro, and D-6 Dialysate meter.

a. Fill and rinse the conductivity cell three times with a 442 standard solution. In this example, we’re using 442-3000.

b. Refill conductivity cell with same standard solution you rinsed with.

c. Press

TDS

 

 

 

 

 

then press

 

.CAL key

 

 

 

 

The “CAL” icon will appear in the top center of the display. In this example, the reading shows 2988.

d. Press

Up

 

 

 

 

 

or

Down

 

 

 

 

 

to step the displayed value toward the standard’s value.

In this example, we’re pressing

 

Up

 

 

 

 

 

to go down from 2988 to 3000. You can also hold a key down to scroll rapidly.

e. Press

 

CAL key

 

 

 

 

 

once to confirm the new value and end the calibration.

You can find technical advice and videos, the calibration solutions you need, and reliable Myron L meters
at MyronLMeters.com
 
 

 

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

Ultrameter II Calibrate TDS on the 6PII

Posted by 22 Mar, 2014

TweetUltrameter II 6PII how to calibrate TDS, total dissolved solids. Learn how to test water samples, and calibration for the Ultrameter II.

Subscribe ->
Watch on YouTube: http://www.youtube.com/watch?v=gWqPQTcOwFY

Ultrameter II 6PII how to calibrate TDS, total dissolved solids. Learn how to test water samples, and calibration for the Ultrameter II.

Categories : Videos

Ultrameter: Measuring Conductivity, TDS and Resistivity: MyronLMeters.com

Posted by 1 Mar, 2014

TweetPlease note:  These procedures apply to Ultrameters, Pool Pros, Tech Pros, and D-4 and D-6 dialysate meters. Measuring Conductivity & TDS 1. Rinse cell cup 3 times with sample to be measured. (This conditions the temperature compensation network and prepares the cell.) 2. Refill cell cup with sample. 3. Press COND or TDS. 4. Take […]

Please note:  These procedures apply to Ultrameters, Pool Pros, Tech Pros, and D-4 and D-6 dialysate meters.

Measuring Conductivity & TDS

1. Rinse cell cup 3 times with sample to be measured. (This conditions

the temperature compensation network and prepares the cell.)

2. Refill cell cup with sample.

3. Press COND or TDS.

4. Take reading. A display of [- - - -] indicates an over range condition.

Measuring Resistivity

Resistivity is for low conductivity solutions. In a cell cup the value may drift from trace contaminants or absorption from atmospheric gasses, so measuring a flowing sample is recommended.

1. Ensure pH protective cap is secure to avoid contamination.

2. Hold instrument at 30° angle (cup sloping downward).

3. Let sample flow continuously into conductivity cell with no aeration.

4. Press RES key; use best reading.

NOTE: If reading is lower than 10 kilohms display will be dashes: [ - - - - ]. Use Conductivity.

If you have further questions, please watch our Ultrameter 6P product overview video here: http://blog.myronlmeters.com/ultrameter-ii-product-review/

 IV. AFTER USING THE ULTRAMETER II

Maintenance of the Conductivity Cell

Rinse out the cell cup with clean water. Do not scrub the cell. For oily films, squirt in a foaming non-abrasive cleaner and rinse. Even if a very active chemical discolors the electrodes, this does not affect the accuracy; leave it alone.

Myron L Meters is the premier internet retailer of Myron L meters, solutions, parts and accessories. Save 10% on the Ultrameter II 6PFCe when you order online at MyronLMeters.com.

Categories : Application Advice, Technical Tips

Conductivity Conversion to TDS in the Ultrameter: MyronLMeters.com

Posted by 1 Mar, 2014

TweetElectrical conductivity indicates solution concentration and ionization of the dissolved material. Since temperature greatly affects ionization, conductivity measurements are temperature dependent and are normally corrected to read what they would be at 25°C. A.           How It’s Done Once the effect of temperature is removed, the compensated conductivity is a function of the concentration (TDS). Temperature […]

Electrical conductivity indicates solution concentration and ionization of the dissolved material. Since temperature greatly affects ionization, conductivity measurements are temperature dependent and are normally corrected to read what they would be at 25°C.

A.           How It’s Done

Once the effect of temperature is removed, the compensated conductivity is a function of the concentration (TDS). Temperature compensation of the conductivity of a solution is performed automatically by the internal processor with data derived from chemical tables. Any dissolved salt at a known temperature has a known ratio of conductivity to concentration. Tables of conversion ratios referenced to 25°C have been published by chemists for decades.

B.           Solution Characteristics

Real world applications have to measure a wide range of materials and mixtures of electrolyte solutions. To address this problem, industrial users commonly use the characteristics of a standard material as a model for their solution, such as KCl, which is favored by chemists for its stability.

Users dealing with sea water, etc., use NaCl as the model for their concentration calculations. Users dealing with freshwater work with mixtures including sulfates, carbonates and chlorides, the three predominant components (anions) in freshwater that Myron L calls “Natural Water”. These are modeled in a mixture called “442™” which Myron L uses as a calibration standard, as it does standard KCl and NaCl solutions.

The Ultrameter II contains algorithms for these 3 most commonly referenced compounds. The solution type in use is displayed on the left. Besides KCl, NaCl, and 442, there is the User choice. The benefit of the User solution type is that one may enter the temperature compensation and TDS ratio by hand, greatly increasing accuracy of readings for a specific solution. That value remains a constant for all measurements and should be reset for different dilutions or temperatures.

C.           When does it make a lot of difference?

First, the accuracy of temperature compensation to 25°C determines the accuracy of any TDS conversion. Assume we have industrial process water to be pretreated by RO. Assume it is 45°C and reads 1500 µS uncompensated.

1.         If NaCl compensation is used, an instrument would report 1035 µS compensated, which corresponds to 510 ppm NaCl.

2.         If 442 compensation is used, an instrument would report 1024 µS compensated, which corresponds to 713 ppm 442.

The difference in values is 40%.

In spite of such large error, some users will continue to take data in the NaCl mode because their previous data gathering and process monitoring was done with an older NaCl referenced device.

Selecting the correct Solution Type on the Ultrameter II will allow the user to attain true TDS readings that correspond to evaporated weight.

If none of the 3 standard solutions apply, the User mode must be used.

TEMPERATURE COMPENSATION (Tempco) and TDS DERIVATION

The Ultrameter II contains internal algorithms for characteristics of the 3 most commonly referenced compounds. The solution type in use is displayed on the left. Besides KCl, NaCl, and 442, there is the User choice. The benefit of User mode is that one may enter the tempco and TDS conversion values of a unique solution via the keypad.

A. Conductivity Characteristics
When taking conductivity measurements, the Solution Selection determines the characteristic assumed as the instrument reports what a measured conductivity would be if it were at 25°C. The characteristic is represented by the tempco, expressed in %/°C. If a solution of 100 µS at 25°C increases to 122 µS at 35°C, then a 22% increase has occurred over this change of 10°C. The solution is then said to have a tempco of 2.2 %/°C. Tempco always varies among solutions because it is dependent on their individual ionization activity, temperature and concentration. This is why the Ultrameter II features mathematically generated models for known salt characteristics that also vary with concentration and temperature.

B. Finding the Tempco of an Unknown Solution

One may need to measure compensated conductivity of some solution unlike any of the 3 standard salts. In order to enter a custom fixed tempco for a limited measurement range, enter a specific value through the User function. The tempco can be determined by 2 different methods:

1. Heat or cool a sample of the solution to 25°C, and measure its conductivity. Heat or cool the solution to a typical temperature where it is normally measured. After selecting User function, set the tempco to 0 %/°C as in Disabling Temperature Compensation, pg. 15 (No compensation). Measure the new conductivity and the new temperature. Divide the % decrease or increase by the 25°C value. Divide that difference by the temperature difference.

2. Heat or cool a sample of the solution to 25°C, and measure its conductivity. Change the temperature to a typical measuring temperature. Set the tempco to an expected value as in User Programmable Temperature Compensation, pg. 15. See if the compensated value is the same as the 25°C value. If not, raise or lower the tempco and measure again until the 25°C value is read.

C. Finding the TDS Ratio of an Unknown Solution

Once the effect of temperature is removed, the compensated conductivity is a function of the concentration (TDS).

There is a ratio of TDS to compensated conductivity for any solution, which varies with concentration. The ratio is set during calibration in User mode as in User Programmable Conductivity to TDS Ratio, pg. 16.
A truly unknown solution has to have its TDS determined by evaporation and weighing. Then the solution whose TDS is now known can be measured for conductivity and the ratio calculated. Next time the same solution is to be measured, the ratio is known.

ph and ORP (6PFCE)

1. pH as an Indicator (6PFCE)

pH is the measurement of Acidity or Alkalinity of an aqueous solution. It is also stated as the Hydrogen Ion activity of a solution. pH measures the effective, not the total, acidity of a solution.
A 4% solution of acetic acid (pH 4, vinegar) can be quite palatable, but a 4% solution of sulfuric acid (pH 0) is a violent poison. pH provides the needed quantitative information by expressing the degree of activity of an acid or base. In a solution of one known component, pH will indicate concentration indirectly. However, very dilute solutions may be very slow reading, just because the very few ions take time to accumulate.

2. pH Units (6PFCE)

The acidity or alkalinity of a solution is a measurement of the relative availabilities of hydrogen (H+) and hydroxide (OH-) ions. An increase in (H+) ions increases acidity, while an increase in (OH-) ions increases alkalinity. The total concentration of ions is fixed as a characteristic of water, and balance would be 10-7 mol/liter (H+) and (OH-) ions in a neutral solution (where pH sensors give 0 voltage).
pH is defined as the negative logarithm of hydrogen ion concentration. Where (H+) concentration falls below 10-7, solutions are less acidic than neutral, and therefore are alkaline. A concentration of 10-9 mol/liter of (H+) would have 100 times less (H+) ions than (OH-) ions and be called an alkaline solution of pH 9.

3. The pH Sensor (6PFCE)

The active part of the pH sensor is a thin glass surface that is selectively receptive to hydrogen ions. Available hydrogen ions in a solution will accumulate on this surface and a charge will build up across the glass interface. The voltage can be measured with a very high impedance voltmeter circuit; the dilemma is how to connect the voltmeter to solution on each side.
The glass surface encloses a captured solution of potassium chloride holding an electrode of silver wire coated with silver chloride. This is the most inert connection possible from a metal to an electrolyte. It can
still produce an offset voltage, but using the same materials to connect to the solution on the other side of the membrane causes the 2 equal offsets to cancel.
The problem is, on the other side of the membrane is an unknown test solution, not potassium chloride. The outside electrode, also called the Reference Junction, is of the same construction with a porous plug in place of a glass barrier to allow the junction fluid to contact the test solution without significant migration of liquids through the plug material. Figure 33 shows a typical 2 component pair. Migration does occur, and this limits the lifetime of a pH junction from depletion of solution inside the reference junction or from contamination. The junction may be damaged if dried out because insoluble crystals may form in a layer, obstructing contact with test solutions.

Capture

Figure 33

 

Glass Surface

H+ ions

Junction plug
Platinum button

 

KCl solution

 

 

Glass

 

 

Electrode wires

 

 

 

4. The Myron L Integral pH Sensor (6PFCE)

The sensor in the Ultrameter II (see Figure 34) is a single construction in an easily replaceable package. The sensor body holds an oversize solution supply for long life. The reference junction “wick” is porous to provide a very stable, low permeable interface, and is located under the glass pH sensing electrode. This construction combines all the best features of any pH sensor known.

5. Sources of Error (6PFCE)

The most common sensor problem will be a clogged junction because a sensor was allowed to dry out. The symptom is a drift in the “zero” setting at 7 pH. This is why the Ultrameter II 6PFCE does not allow more than 1 pH unit of offset during calibration. At that point the junction is unreliable.

b. Sensitivity Problems

Sensitivity is the receptiveness of the glass surface. A film on the surface can diminish sensitivity and cause a long response time.

c. Temperature Compensation

pH sensor glass changes its sensitivity slightly with temperature, so the further from pH 7 one is, the more effect will be seen. A pH of 11 at 40°C would be off by 0.2 units. The Ultrameter II 6PFCE senses the sensor well temperature and compensates the reading.

B. ORP/Oxidation-Reduction Potential/REDOX (6PFCE)

1. ORP as an Indicator (6PFCE)

ORP is the measurement of the ratio of oxidizing activity to reducing activity in a solution. It is the potential of a solution to give up electrons (oxidize other things) or gain electrons (reduce).
Like acidity and alkalinity, the increase of one is at the expense of the other, so a single voltage is called the Oxidation-Reduction Potential, with a positive voltage showing, a solution wants to steal electrons (oxidizing agent). For instance, chlorinated water will show a positive ORP value.

2. ORP Units (6PFCE)

ORP is measured in millivolts, with no correction for solution temperature. Like pH, it is not a measurement of concentration directly, but of activity level. In a solution of only one active component, ORP indicates concentration. Also, as with pH, a very dilute solution will take time to accumulate a readable charge.

3. The ORP Sensor (6PFCE)
An ORP sensor uses a small platinum surface to accumulate charge without reacting chemically. That charge is measured relative to the solution, so the solution “ground” voltage comes from a reference junction – same as the pH sensor uses.

4. The Myron L ORP Sensor (6PFCE)

Figure 34, pg. 45, shows the platinum button in a glass sleeve. The same reference is used for both the pH and the ORP sensors. Both pH and ORP will indicate 0 for a neutral solution. Calibration at zero compensates for error in the reference junction. A zero calibration solution for ORP is not practical, so the Ultrameter II 6PFCE uses the offset value determined during calibration to 7 in pH calibration (pH 7 = 0 mV). Sensitivity of the ORP surface is fixed, so there is no gain adjustment either.

5. Sources of Error (6PFCE)

The basics are presented in pH and ORP, pg. 44, because sources of error are much the same as for pH. The junction side is the same, and though the platinum surface will not break like the glass pH surface, its protective glass sleeve can be broken. A surface film will slow the response time and diminish sensitivity. It can be cleaned off with detergent or acid, as with the pH glass.

C. Free Chlorine

1. Free Chlorine as an Indicator of Sanitizing Strength Chlorine, which kills bacteria by way of its power as an oxidizing agent, is the most popular germicide used in water treatment. Chlorine is not only used as a primary disinfectant, but also to establish a sufficient residual level of Free Available Chlorine (FAC) for ongoing disinfection.

FAC is the chlorine that remains after a certain amount is consumed by killing bacteria or reacting with other organic (ammonia, fecal matter) or inorganic (metals, dissolved CO2, Carbonates, etc) chemicals in solution. Measuring the amount of residual free chlorine in treated water is a well accepted method for determining its effectiveness in microbial control.

The Myron L  FCE method for measuring residual disinfecting power is based on ORP, the specific chemical attribute of chlorine (and other oxidizing germicides) that kills bacteria and microbes.

2. FCE Free Chlorine Units

The 6PIIFCE is the first handheld device to detect free chlorine directly, by measuring ORP. The ORP value is converted to a concentration reading (ppm) using a conversion table developed by Myron L Company through a series of experiments that precisely controlled chlorine levels and excluded interferants.

Other test methods typically rely on the user visually or digitally interpreting a color change resulting from an added reagent-dye. The reagent used radically alters the sample’s pH and converts the various chlorine species present into a single, easily measured species. This ignores the effect of changing pH on free chlorine effectiveness and disregards the fact that some chlorine species are better or worse sanitizers than others.

The Myron L 6PIIFCE avoids these pitfalls. The chemistry of the test sample is left unchanged from the source water. It accounts for the effect of pH on chlorine effectiveness by including pH in its calculation. For these reasons, the Ultrameter II’s FCE feature provides the best reading-to-reading picture of the rise and fall in sanitizing effectivity of free available chlorine.

The 6PIIFCE also avoids a common undesirable characteristic of other ORP-based methods by including a unique Predictive ORP value in its FCE calculation. This feature, based on a proprietary model for ORP sensor behavior, calculates a final stabilized ORP value in 1 to 2 minutes rather than the 10 to 15 minutes or more that is typically required for an ORP measurement.

The Myron L Ultrameter II 6PFCe is available at MyronLMeters.com, the premier internet retailer of Myron L products. Save 10% on the Myron L Ultrameter II6 PFCe when you order online here: http://www.myronlmeters.com/Myron-L-6P-Ultrameter-II-Multiparameter-Meter-p/dh-umii-6pii.htm

 

Categories : Application Advice, Technical Tips

Cleaning The Ultrameter II 6P Sensors: MyronLMeters.com

Posted by 1 Mar, 2014

TweetConductivity/TDS/Resistivity The conductivity cell cup should be kept as clean as possible. Flushing with clean water following use will prevent buildup on electrodes. However, if very dirty samples — particularly scaling types — are allowed to dry in the cell cup, a film will form. This film reduces accuracy. When there are visible films of […]

Conductivity/TDS/Resistivity

The conductivity cell cup should be kept as clean as possible. Flushing with clean water following use will prevent buildup on electrodes. However, if very dirty samples — particularly scaling types — are allowed to dry in the cell cup, a film will form. This film reduces accuracy. When there are visible films of oil, dirt, or scale in the cell cup or on the electrodes, use isopropyl alcohol or a foaming non-abrasive household cleaner. Rinse out the cleaner and your Ultrameter II is again ready to use.

pH/ORP (6PFCE)

The unique pH/ORP sensor in your Ultrameter II  is a nonrefillable combination type that features a porous liquid junction. It should not be allowed to dry out. To keep it from drying out and to prolong the life of the sensor, use SS sensor storage solution found here: http://www.myronlmeters.com/Myron-L-pH-ORP-Sensor-Storage-Solutions-32-oz-p/s-ssq.htm.  However, if this occurs, the sensor may sometimes be rejuvenated by first cleaning the sensor well with Isopropyl alcohol or a liquid spray cleaner such as Windex™ or Fantastic™ and rinsing well. Do not scrub or wipe the pH/ORP sensor.

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Then use one of the following methods:

1.            Pour a HOT salt solution ~60°C/140°F — a potassium chloride (KCI) solution such as Myron L pH/ORP Sensor Storage Solution is preferable, but HOT tap water with table salt (NaCl) will work fine — in the sensor well and allow to cool. Retest.

or

2.            Pour DI water in the sensor well and allow to stand for no more than 4 hours (longer can deplete the reference solution and damage the glass bulb). Retest. If neither method is successful, the sensor must be replaced.

“Drifting” can be caused by a film on the pH sensor bulb and/or reference. Use isopropyl alcohol (IPA) or spray a liquid cleaner such as Windex™ or Fantastic™ into the sensor well to clean it. The sensor bulb is very thin and delicate. Do not scrub or wipe the pH/ORP sensor. Leaving high pH (alkaline) solutions in contact with the pH sensor for long periods of time is harmful and will cause damage. Rinsing such liquids from the pH/ORP sensor well and refilling it with Myron L Storage Solution, a saturated KCl solution, pH 4 buffer, or a saturated solution of table salt and tap water, will extend the useful life.

Samples containing chlorine, sulfur, or ammonia can “poison” any pH electrode. If it is necessary to measure the pH of any such sample, thoroughly rinse the sensor well with clean water immediately after taking the measurement. Any sample element that reduces (adds an electron to) silver, such as cyanide, will attack the reference electrode.

Replacement sensors are available here:  http://www.myronlmeters.com/Myron-L-RPR-Ultrameter-pH-ORP-Sensor-p/a-rpr.htm

Myron L Meters is your best internet source for Ultrameter 6P parts and accessories.  You can always save 10% on Myron L meters when you order online at MyronLMeters.com.

 

Categories : Care and Maintenance, Technical Tips