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

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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.



 

 

 

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Ultrapen PT2 Product Review – Myron L Meters

Posted by 6 Apr, 2014

TweetUltrapen PT2 product review. Myron L Meters presents a review of the Ultrapen PT2 that measures pH. In this video, we cover the steps for measuring pH, changing the temperature setting, changing the pH measurement mode, and overall features.Order the Ultrapen PT2 here: http://www.myronlmeters.com/Myron-L-PT2-Ultrapen-Multiparameter-pH-temperature-p/dh-up-pt2-ss.htm

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Ultrapen PT2 product review. Myron L Meters presents a review of the Ultrapen PT2 that measures pH. In this video, we cover the steps for measuring pH, changing the temperature setting, changing the pH measurement mode, and overall features.

Order the Ultrapen PT2 here: http://www.myronlmeters.com/Myron-L-PT2-Ultrapen-Multiparameter-pH-temperature-p/dh-up-pt2-ss.htm

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Ultrapen PT2 Product Review – Myron L Meters

Posted by 5 Apr, 2014

TweetUltrapen PT2 product review. Myron L Meters presents a review of the Ultrapen PT2 that measures pH. In this video, we cover the steps for measuring pH, changing the temperature setting, changing the pH measurement mode, and overall features. Order the Ultrapen PT2 here: http://www.myronlmeters.com/Myron-L-PT2-Ultrapen-Multiparameter-pH-temperature-p/dh-up-pt2-ss.htm

Subscribe ->
Watch on YouTube: http://www.youtube.com/watch?v=E8TEZY8ZztU

Ultrapen PT2 product review. Myron L Meters presents a review of the Ultrapen PT2 that measures pH. In this video, we cover the steps for measuring pH, changing the temperature setting, changing the pH measurement mode, and overall features.

Order the Ultrapen PT2 here: http://www.myronlmeters.com/Myron-L-PT2-Ultrapen-Multiparameter-pH-temperature-p/dh-up-pt2-ss.htm

Categories : Videos

Calibrating the Ultrapen PT2 pH Tester: MyronLMeters.com

Posted by 3 Apr, 2014

Tweet I.      Calibration The factory recommends calibrating the Ultrapen PT2 pH tester twice a month, depending on usage. However, you should check the calibration whenever measurements are not as expected. 3-point Wet Calibration is most accurate and is recommended. NOTE: If the measurement is NOT within calibration limits for any reason, “Error” will display. Check […]

I.      Calibration

The factory recommends calibrating the Ultrapen PT2 pH tester twice a month, depending on usage. However, you should check the calibration whenever measurements are not as expected. 3-point Wet Calibration is most accurate and is recommended.

NOTE: If the measurement is NOT within calibration limits for any reason, “Error” will display. Check to make sure you are using a proper pH buffer solution. If the solution is correct, clean the glass bulb of the sensor with a cotton swab soaked in isopropyl alcohol. Restart calibration.

NOTE: Small bubbles trapped in the sensor may give a false calibration. After calibration is completed, measure the pH buffer solutions again 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 pen to power off and start over.

A.    Calibration Preparation

  1. For maximum accuracy, fill 2 clean containers with each pH buffer. Arrange them in such a way that you can clearly remember which is the rinse solution and which is the calibration buffer. If you don’t have enough buffer, you can use 1 container of each buffer for calibration and 1 container of clean water for all rinsing. Always rinse the pH sensor between buffer solutions.

2.   Ensure the pH sensor is clean and free of debris.

B.    3-Point Calibration

Use pH 7, 4 and 10 buffers for 3-point calibration.

1. Thoroughly rinse the pen by submerging the sensor in pH 7 buffer rinse solution and swirling it around.

2. Push and release the push button to turn the unit on.
3. Push and hold the push button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL” and “ESC”.
4. Release the button when “CAL” displays. The display will indicate “CAL” and the LED will flash rapidly. 
5. While the LED flashes rapidly, dip the pen in pH 7 buffer calibration solution so that the sensor is completely submerged. 
6. While the LED flashes slowly, the pH calibration point will display along with “CAL”. Swirl the pen around to remove bubbles, keeping the sensor submerged.
7.   If the pH 7 calibration is successful, the display will indicate “SAVED”, then “PUSHCONT” will be displayed.

8.   Push and release the push button to continue. The LED will begin flash rapidly.Repeat steps 5 through 8 with pH 4 and 10 buffer calibration solutions.After the 3rd calibration point is successfully saved, the display will indicate “SAVED” and power off.Verify calibration by retesting the calibration solution.

C.    2-Point Calibration

Use pH 7 and 4 or 10 buffers for 2-point calibration.

  1. Thoroughly rinse the pen by submerging the sensor in pH 7 buffer rinse solution and swirling it around.
  2. Push and release the push button to turn the unit on.
  3. Push and hold the push button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL” and “ESC”.
  4. Release the button when “CAL” displays. The display will indicate “CAL” and the LED will flash rapidly.
  5. While the LED flashes rapidly, dip the pen in pH 7 buffer calibration solution so that the sensor is completely submerged.
  6. While the LED flashes slowly, the pH calibration point will display along with “CAL”. Swirl the pen around to remove bubbles, keeping the sensor submerged.
  7. If the pH 7 calibration is successful, the display will indicate “SAVEd”, then “PUSHCONT” will be displayed.
  8. Push and release the push button to continue. The LED will begin flashimg rapidly.

Repeat steps 5 through 7 with pH 4 or 10 buffer calibration solution.

Leave the pen in the same buffer solution until the unit powers off. The offset will be applied to the remaining calibration point.
Verify calibration by retesting the calibration solution.

 

D.    1-Point Calibration

Use pH 7, 4 or 10 buffer for 1-point calibration.

  1. Thoroughly rinse the pen by submerging the sensor in pH buffer rinse solution and swirling it around.
  2. Push and release the push button to turn the unit on.
  3. Push and hold the push button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL” and “ESC”.
  4. Release the button when “CAL” displays. The display will indicate “CAL” and the LED will flash rapidly.
  5. While the LED flashes rapidly, dip the pen in pH buffer calibration solution so that the sensor is completely submerged.
  6. While the LED flashes slowly, the pH calibration point will display along with “CAL”; swirl the pen around to remove bubbles, keeping the sensor submerged.

If the pH calibration is successful, the display will indicate “SAVEd”, then “PUSHCONT” will be displayed. “PUSHCONT” will not display if you calibrated 4 or 10.

Leave the pen in the same buffer solution until the unit powers off. The offset will be applied to the remaining calibration points.

Verify calibration by retesting the calibration solution.

E.    Factory Calibration

When pH buffers are not available, the PT2 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 unit to factory calibration:

  1. Push and release the push button.
  2. Push and hold the push button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL” 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 PT2 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 PT2 pH Tester Measurement: MyronLMeters.com

Posted by 3 Apr, 2014

Tweet Measuring pH and Temperature with the Ultrapen PT2 NOTE: Selecting “ESC” from any menu immediately powers the unit off without saving changes. I. Temperature Unit Selection The PT2 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 […]

Capture

Measuring pH and Temperature with the Ultrapen PT2

NOTE: Selecting “ESC” from any menu immediately powers the unit off without saving changes.

I. Temperature Unit Selection

The PT2 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 unit on.
2. Push and hold the button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “ModE SEL” 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. pH Mode Selection

The PT2 allows you to select the pH measurement mode you prefer:
Hold (once stabilized, the readings are captured then displayed) or
LIVE (real-time readings are displayed continuously during measurement)
To set the pH measurement mode preference:
1. Push and release the push button to turn the unit on.
2. Push and hold the button. The display will alternate between “CAL”, “FAC CAL”, “ºCºF TEMP”, “Mode SEL” 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 unit will power off.

III. pH Measurement

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

LED Signal Action Duration
Rapid Flashing Dip pen in solution. 6 sec
Slow Flashing Measurement in process.
In LIVE mode, the readings are displayed. In LIVE mode, note measurement values. 10-30 sec in Hold mode 60 sec in LIVE mode
Solid Light (Hold mode only) Measurement is complete.
In Hold mode, captured readings are displayed. In Hold mode, note measurement values. 6 sec

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

NOTE: If you cannot dip the pen 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. If measuring from a container, submerge the pen and swirl it around in FRESH sample solution 3 times. Alternatively, 30 seconds under a stream or of swirling in a body of water is sufficient to prepare the sensor for measurement.
2. Remove pen from solution. (Fill the container one more time with FRESH
sample solution, if applicable.) Then push and release the push button.
3. Grasp the pen by its case with your fingers positioned between the display and
the battery cap to avoid sample contamination.
4. While the LED flashes rapidly, dip the pen in FRESH sample solution so that the sensor is completely submerged. If you do not submerge the sensor in solution before the fl 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 sensor submerged.
a. In Hold mode when the LED turns on solid, remove the pen from solution.

The display will alternate between the final pH and temperature readings.
Note the readings for your records.
b. In LIVE mode allow the pen to remain in solution while the LED flashes slowly. The display will alternate between live pH and temperature readings. Note the readings for your records. LIVE measurement will time out after 1 minute OR push and release the push button to power the pen off at any time during LIVE measurement.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT2 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Product Updates

Ultrapen PT2 pH Tester Features: MyronLMeters.com

Posted by 3 Apr, 2014

TweetThe ULTRAPEN™ PT2 pH Pen is designed to be extremely accurate, fast and simple to use in diverse water quality applications. Advanced features include automatic temperature compensation; highly stable microprocessor-based circuitry; user-intuitive design; and waterproof housing. A true one- handed instrument, the PT2 is easy to calibrate and easy to use. To take a measurement, […]

The ULTRAPEN™ PT2 pH Pen is designed to be extremely accurate, fast and simple to use in diverse water quality applications. Advanced features include automatic temperature compensation; highly stable microprocessor-based circuitry; user-intuitive design; and waterproof housing. A true one- handed instrument, the PT2 is easy to calibrate and easy to use. To take a measurement, you simply push 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. Battery Cap — provides access to battery for replacement.
3. Pocket Clip — holds pen to shirt pocket for secure storage.
4. Battery Indicator — indicates charge left in battery.
5. Display — displays measurements, menu options, battery indicator, and firmware revision (during power-up).
6. LED Indicator Light — indicates when to dip instrument in solution, when measurement is in progress, and when to remove instrument from solution.
7. pH Sensor — measures hydrogen ion concentration of solution.
8. Soaker Cap — contains a sponge soaked with pH Sensor Storage Solution to maintain sensor hydration. To remove, twist the soaker cap while pulling off. To replace, fill the soaker cap with storage solution just until the sponge is covered. Pour out any excess solution. Twist the 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 the scoop onto the sensor
while shifting side-to-side. To remove, pull the scoop off while shifting side-to-side. Verify the pH sensor remained fully inserted into the PT2. If not, reinstall per pH Sensor Replacement, p. 5. To use, pour solution into the scoop or hold the scoop directly under a vertical stream to collect sample.
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.

SPECIFICATIONS
pH Temperature
Range: 0.00-14.00pH 0-71°C/32-160°F
Accuracy: ± 0.01pH (After Wet Calibration) ±0.1ºC/±0.1ºF
Repeatability: ± 0.01pH ±0.1ºC/±0.1ºF
Resolution: 0.01pH 0.1ºC/0.1ºF
Time to Reading Stabilization: 10-30 seconds
Power Consumption: Active Mode 37mA, Sleep Mode 2µA
Temperature Compensation: Automatic to 25ºC
Physical Dimensions: 17.15cm L x 1.59cm D or 6.75in. L x 0.625in. D
Weight: 54g/1.9oz. (without soaker cap and lanyard)
Case Material: Anodized Aircraft Aluminum with Protective Coating
Battery Type: N type, Alkaline, 1.5V
Calibration Solutions: pH4, pH7, pH10
Operating/Storage Temperature: 0-55ºC or 32-131ºF
Enclosure Ratings: IP67 and NEMA6
EN61236-1: 2006 – Annex A: 2008: Electrostatic discharge to case of instrument may cause PT2 to spontaneously power on. If this happens, the PT2 will power itself off within seconds.

MyronLMeters.com is the premier internet retailer of the Ultrapen PT2 and other reliable Myron L meters. Save 10% on Myron L meters when you order online HERE.

Categories : Product Updates

Ultrameter II Calibrate pH for the 6PII

Posted by 22 Mar, 2014

TweetUltrameter II Calibrate pH for the 6PII.

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Ultrameter II Calibrate pH for the 6PII.

Categories : Videos

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

Horticulture Applications: MyronLMeters.com

Posted by 13 Nov, 2013

Tweet                    WHY ARE TESTS SO IMPORTANT? Modern growing practices include scientific evaluations of soil, water, fertilizers, diseases, etc. While some tests are best performed by a laboratory, others can be easily conducted on location, saving time and money. Three tests in particular, EC, pH, and ALKALINITY, […]

The Myron L Ag-6/pH

 

 

 

 

 

 

 

 

 

 

WHY ARE TESTS SO IMPORTANT?

Modern growing practices include scientific evaluations of soil, water, fertilizers, diseases, etc. While some tests are best performed by a laboratory, others can be easily conducted on location, saving time and money. Three tests in particular, EC, pH, and ALKALINITY, can reveal valuable information about water quality, soil salinity, and fertilizer concentration. Our portable AGRI-METERS™ provide you with a simple, fast, and accurate means of testing these parameters.

WHAT IS ELECTRICAL CONDUCTIVITY (EC)?

EC is the measurement of a solution’s ability to conduct an electrical current. For horticultural applications, the unit of measure is often expressed as millimhos. Absolutely pure water is actually a poor electrical conductor. It is the substances (or electrolytes) dissolved in the water which determine how conductive the solution will be.

Therefore, EC can be an excellent indicator of:

1. Water quality

2. Soil salinity

3. Fertilizer concentration

EC AND WATER QUALITY

The quality of irrigation water is one of the most critical factors influencing your growing operation. It is important to have a complete water analysis performed on a regular basis. Environmental conditions such as drought, changing seasons, heavy rainfall, etc., can cause the concentrations of dissolved salts in your water to vary significantly. These dissolved salts (i.e. calcium, sodium, etc.) can directly affect your plants’ health and, over time, render even the best soil useless.

You can monitor your overall water quality by testing its electrical conductivity with an AGRI-METER™. The higher the EC, the more salts are dissolved in your water. By comparing your EC with previous readings, you can tell if any dramatic changes have occurred. Nutrient deficiencies are possible when water is too pure (low EC) or if the relative concentrations of some nutrients are unbalanced (i.e. calcium/magnesium). On the other hand, nutrient toxicities or osmotic interferences can also be traced to water quality. Water EC of even one millimho or below can cause problems. High EC readings of more than two millimhos can suggest serious problems, and special cultural procedures may be required.

EC AND SOIL SALINITY

“Water, water, everywhere, but not a drop to drink” is an old saying that applies to your plants when the soil salinity becomes too high. Salts from irrigation water and fertilizers tend to accumulate in your soil or growing media. High soil salinity disrupts the normal osmotic balance in plant roots. In severe cases a plant will become dehydrated even when the soil is wet. Symptoms of high soil salinity include: leaf chlorosis and necrosis, leaf drop, root death, nutrient deficiency symptoms, and wilting. All too often these symptoms are not recognized as being caused by soluble salts in the growing media. Sampling your soil and testing the EC of an extract can reveal important information about a soil’s suitability and your crop’s health.

Samples should be representative of different depths and locations. An easy-to-perform extract method is available with a Soil Test Kit. A 2:1 or 5:1 water-to-soil ratio is made using the small vials provided. Soil test labs often use a method that calls for testing the EC of an extract from a thicker slurry. Therefore, you may see higher soil EC readings from a lab. It is important to standardize your sampling, extract, and testing methods. This will keep the difference between lab and field testing to a predictable factor.

EC AND FERTILIZER CONCENTRATION

You know how important fertilizer is to your plants, but do you know how accurate your fertilizer dosage is? Relying on traditional proportional methods is risky to plants and can waste expensive fertilizer. Improperly mixed fertilizer or a malfunctioning injector can lead to less than optimal results or even a disastrous loss of crops. Many fertilizer companies now recommend using a simple EC test to verify correct fertilizer concentrations. Many growers check their fertilizer injectors on a weekly basis, or they use a continuous EC monitor.

Fertilizer companies and suppliers often can provide a chart relating EC to parts per million concentrations of their various fertilizers. If one is not available for the fertilizer you use, carefully make some stock solutions at commonly used strengths and test their EC. This will give you a data base for future reference.

To test the EC of fertilizer solutions:

  1. Test and record the EC of the water to be mixed with the fertilizer.
  2. Test the conductivity of the fertilizer and water mixture.
  3. Subtract the water conductivity determined in #1 above.
  4. The resulting figure is an accurate indication of how much fertilizer is present (a higher conductivity means more fertilizer).

Important note: Interpretation of results differs from formula to formula and even among manufacturers of the same formula. Obtain the proper EC charts from the fertilizer company.

Myron L Meters sells both portable and inline instrumentation to make your fertilizer monitoring easy. Myron L AGRI-METERS™, AG-5 and AG6/PH, TH1, waterproof TECHPRO II™ models TP1, TPH1 and TH1, and waterproof ULTRAMETER II™ models 4P and 6PFCEare handheld instruments which make fertilizer testing as simple as filling a cup and pushing a button.

The Myron L 750 Series II™ EC Monitor/controllers can be used to continuously monitor your fertilizer concentration. Their “alarm” relay circuit acts as a safeguard in a fertilizer injection system or even as the main controller for your injector. A 0-10 VDC output for chart recorders or PLC (SCADA) input is standard on all monitor/controller models.

IMPORTANCE OF pH

pH, the measure of acidity or basicity, should be included in any soil or water test. It is well documented that growing media pH is critical to successful plant growth. This is especially true for new soilless mixes and hydroponics. pH affects the roots’ ability to absorb many plant nutrients. Examples include iron and manganese, which are insoluble at high pHs and toxic at low pHs. pH also directly affects the health of necessary micro-organisms in soil.

The effectiveness of pesticides and growth regulators can be severely limited by spray water pH that is either too low or too high.

ALKALINITY

It is important to note that testing the pH of irrigation water reveals only part of the story. Testing water alkalinity (bicarbonates and carbonates) is much more important than generally recognized. Alkalinity dictates how much influence the water’s pH will have on your soil and nutrient availability. In addition, alkalinity has a very great effect on the ease or difficulty of reducing the pH of water.

 

 

Categories : Application Advice, Case Studies & Application Stories