POOLPRO™ Operation Manual MODEL PS9TK 17 June 2013
The PS9 titration kit (with bludock option) Comes with Everything You See Here 3 6 7 12 13 14 15 8 16 9 10 11 17 18 19 1 20 5 2 22 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 4 21 23 PLEASE CHECK THE CONTENTS OF YOUR KIT! POOLPRO™ Model PS9 Cell Extender Model TKCE Foam-lined hard carry case M’PET 100µL fixed volume pipette Model FVMP-100 12 disposable pipette tips 2oz. bottle of Alkalinity Standard Solution Model ALK-1002OZ 2oz.
Instrument Illustration Reference Junction under Glass pH Bulb pH/ORP Sensor (Replaceable) ORP Electrode pH Glass Electrode Conductivity Cell (Built-in Electrodes) Temperature Sensor pH/ORP Sensor Protective Cap Test Value or Titration Prompts or LSI Mode Units Of Measurement mS - millisiemens/cm (millimhos/cm) Preprogrammed variable conductivity/ TDS ratios µS - microsiemens/cm (micromhos/cm) PPM - parts per million °C°F Date & Time displayed here COND Parameters ORP MIN Displayed here: •
I. INTRODUCTION Thank you for selecting the feature-packed POOLPRO™, one of the Myron L Company’s latest in an increasing line of instruments utilizing advanced microprocessor-based circuitry and SMT manufacturing processes. This circuitry makes the instrument extremely accurate, reliable and very easy to use. The POOLPRO™ PS9TK has been designed to include titration measurements for Alkalinity, Hardness and LSI and an LSI Calculator for water balance analysis.
II. FEATURES and SPECIFICATIONS • • • • • • • • • • • • • • • • • A. Features ORP-based FCE Free Chlorine measurement; displays as ppm concentration Alkalinity and Hardness Conductometric Titrations Langelier Saturation Index (LSI) Titrations and Calculator Superior resolution 4 digit LCD displays full 9999 µS/ppm Cond/MIN/SALT/TDS Accuracy of ±1% of reading / ±0.
C. Specification Chart Parameters Ranges Conductivity 0-9999µS/cm 10-200mS/cm in 5 autoranges TDS 0-9999ppm 10-200ppt in 5 autoranges MIN/SALT* 0-9999ppm 10-200ppt in 5 autoranges pH 0-14pH ±.01pH ORP ±999mV 0.00-9.99ppm*** 350≤ORPmV<725 and 0.0≤pH<9.9 725≤ORPmV<825 and 0.0≤pH<8.9 ±1mV ±1mV** 0.01ppm ±0.3ppm <1.00ppm** ±0.2ppm ≥1.00ppm** Free Chlorine (FCE) Alkalinity Titration 10-800ppm Resolution 0.01(<100µS) 0.1(<1000µS) 1.0(<10mS) 0.01(<100mS) 0.1(<200mS) 0.01(<100ppm) 0.
PLEASE NOTE: Because of our commitment to product improvement, the substance and style of this manual may change. When changes are made, the updated manual is posted for download in PDF format from the Myron L Website: www.myronl.
TABLE OF CONTENTS PS9TK Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i Instrument Illustration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 II. FEATURES and SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . 2 A. Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 B. General Specifications . . . . . . . . .
VI. VII. VIII. IX. X. XI. XII. XIII. XIV. XV. XVI. XVII. XVIII. 6 SOLUTION SELECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. Why Solution Selection is Available . . . . . . . . . . . B. The 3 Solution Types . . . . . . . . . . . . . . . . . . . . . . C. Calibration of Each Solution Type . . . . . . . . . . . . D. Procedure to Select a Solution . . . . . . . . . . . . . . . CALIBRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A.
B. C. D. E. F. G. H. I. J. K. L. M. Titration Standard Solutions . . . . . . . . . . . . . . . . . Titration Reagent Solutions . . . . . . . . . . . . . . . . . pH Buffer Solutions . . . . . . . . . . . . . . . . . . . . . . . pH Sensor Storage Solution . . . . . . . . . . . . . . . . . ORP Sensor Conditioner Solution . . . . . . . . . . . . Soft Protective Carry Cases . . . . . . . . . . . . . . . . . Hard Protective Carry Cases . . . . . . . . . . . . . . . . Replacement pH/ORP Sensor . . . . . . . . .
III. RULES of OPERATION A. Operation NOTE: The cell extender does not interfere with normal operation. Using the instrument is simple: • • • • • • • • • • Individual or multiple parameter readings may be obtained by filling individual sensors or entire cell cup area. Rinse the conductivity cell and/or pH/ORP sensor well with test solution 3 times and refill. Temperature and/or measurement extremes will require additional rinses for maximum accuracy.
2. COND, MIN/SALT and TDS Keys These 3 keys are used with solution in the Conductivity Cell. Precautions: • While filling cell cup, ensure no air bubbles cling on the cell wall. • If the proper solution is not selected (KCl, NaCl, 442), refer to Why Solution Selection is Available, pg. 24 and Procedure to Select a Solution, pg. 25. a. COND Key Solution to be tested is introduced into the conductivity cell and a press of displays conductivity with units on the right.
4. pH and ORP/Fr Chl Keys Measurements are made on solution held in the pH/ORP sensor well (ref. pH and ORP/Free Chlorine, pg. 59). The protective cap is removed and the sensor well is filled and rinsed with the sample enough times to completely replace the storage solution. After use, the pH/ORP sensor well must be refilled with Myron L Storage Solution, and the protective cap reinstalled securely (ref. Maintenance of the pH/ORP Sensor, pg. 11 and Cleaning Sensors, 2. pH/ORP, pg. 48). a.
the display and holding either key scrolls the value rapidly. While in calibration or calculator mode, the keys step or scroll the displayed value up or down. While in Memory Recall, the keys scroll the display up and down through the stack of records (ref. Memory Recall, pg. 37). IV. AFTER USING the POOLPRO A. 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 (ref. Cleaning Sensors, pg.
1. Pipette Instructions Always use a clean tip when changing solutions! To install a tip, press the wide end of the tip on the end of the pipette until it is secure. To remove a tip, simply pull it off the end of the Shaft Coupling pipette. Plunger Button CE Plunger Rod 100µl 100 µL NOTE: The accuracy of titration measurements is affected by your technique. Be careful when removing the cap of the cell extender to add reagents.
conductivity cell being careful not to touch the tip to the existing solution. Depress the top of the pipette to the SECOND STOP (all the way down) being careful to keep the tip over the cell. Release the plunger button and let it return to the REST position. 2. T-Plunger Instructions To PLUNGE the cell: With the cell extender installed and solution in the cell, insert the tip of the T-plunger in the cell extender until the arms of the T-plunger are flush against the rim of the cell extender.
b. Hold When the display says to hold (“HOLd”): Hold the instrument steady in the horizontal position while the instrument records a measurement. Agitate and hold as many times as prompted. Allow the display to cycle through all screens, e.g., “EdTA”, “AGit” and “HOLd”, at least once. Continue holding steady until “Pr ES CAL” displays. “HOLd”: When “HOLd” displays, hold the PS9 still with bottom of case parallel to the ground. Hold the PS9 steady before pressing CAL to accept readings. C.
4. Refill cell cup and cell extender with sample solution. 5. Insert T-plunger into open cell extender until the “T” rests flush on the lip of the cell extender. This will cause fluid beyond what is required for titration to overflow the cell extender. 6. Rotate the T-plunger from side to side, allowing the arms of the T-plunger to slide along the rim of the cell extender. 7. Carefully remove the T-plunger so as not to flick or spill remaining sample.
PS9 as prompted, then pressing CAL as prompted. An alkalinity value will display when the titration measurement is complete. 14. Note the value for your records or press MS to store the value. You can begin another Alkalinity titration by pressing ALK. The PS9 will automatically power off after the period of inactivity defined in the AUTO OFF setting (ref. AUTO OFF, pg. 43). E. Measuring Hardness 1.
7. Carefully remove the T-plunger so as not to flick or spill remaining sample. Tap the T-plunger on the side of the cell extender to remove sample that may be stuck to the T-plunger. 8. Press 9. 10. 11. 12. 13. 14. 15. 16. 17. . “CA” alternating with “tdS” displays along with “PPM” sample value. “PrES CAL” displays when the reading stabilizes. Press CAL. “Add” alternating with “C1” will display; then “AGit” alternating with “HOLd” will display.
18. 19. 20. 21. 22. 23. 24. cell, close the cell extender cap securely to prevent any solution from spilling out, then agitate and hold. Repeat as prompted. “PrES CAL” will display. Press CAL to advance to first titration prompt. “Add” alternating with either “EdTA LC” (Reagent H2) or “EdTA HC” (Reagent H3) will display; then “AGit t1” alternating with “HOLd” will display. The number after “t” indicates which titration point you are on. The number “1” here indicates this is the first titration point.
All other values will display as default. You can adjust any or all of the values displayed to determine the effect of the change(s) on the LSI value. 1. Measuring LSI NOTE: The PS9 will automatically power off after the period of inactivity defined in the AUTO OFF setting (ref. AUTO OFF, pg. 43).
To compute saturation index using hypothetical alkalinity, hardness, pH or temperature values: 1. Press . 2. Either the last stored value or the default value of “120” is displayed. 3. Press the UP or DOWN keys to adjust the alkalinity value or leave as displayed. 4. Press CAL to accept and advance to the hardness value screen. Either the last stored value or the default value of “166” is displayed. 5. Press CAL to accept hardness value and advance to the pH value screen.
of table salt and tap water (ref. Cleaning Sensors, 2. pH/ORP, pg. 48). Do not allow pH/ORP sensor to dry out. H. Measuring ORP The POOLPRO features the ability to measure the activity of oxidizing or reducing chemicals in solution as ORP mV. The instrument also includes an innovative Free Chlorine Equivalent (FCE) feature (Measuring Free Chlorine Using FCE, pg. 22) that uses ORP and pH to measure free available chlorine (FAC) concentration in ppm.
1. 2. Measuring ORP Ensure the PS9 is in ORP/FCE mode (ref. ORP/FCE Mode Selection, pg. 21). 2. Remove protective cap by rotating while grasping and pulling up. 3. 4. Rinse sensor well and cell cup 3 times with sample to be measured. Shake out each sample to remove any residual liquid. Refill both sensor well and cell cup with sample. 5. Press 6. Take reading. 7. Press MS to store reading in memory, if desired. .
solution to flow into and out of the sensor well and cell cup for at least 10 seconds. 4. Let sample flow continuously into conductivity cell with no aeration. 5. Allow both the sensor well and cell cup to remain filled with sample. 6. Press . The instrument will begin alternating between a predicted final ORP value and a free chlorine equivalent concentration in ppm. Both readings will change rapidly at first. 7. Wait for the readings to stabilize.
NOTE: If the reading takes longer than 1 minute to stabilize, press after 1 minute to prevent Auto OFF feature from disturbing the measurement process. Annunciators will alert you when either the pH or ORP of the final FCE ppm value are Out of Range (“-Or-”). 7. Press MS to store reading in memory if desired. 4. FCE Best Practices For best results it is recommended that you: 1. Take 3 consecutive FCE measurements and record the readings. 2. Calculate the average of the 3 measurements. Use this value.
C. Calibration of Each Solution Type There is a separate calibration for each of the 4 solution types. Note that calibration of a 442 solution does not affect the calibration of a NaCl solution. For example: Calibration (ref. Conductivity, MIN/SALT or TDS Calibration, pg. 27) is performed separately for each type of solution one wishes to measure (ref. Conductivity/TDS Standard Solutions, pg. 52). D.
VII. CALIBRATION A. Calibration Intervals Generally, calibration is recommended about once per month with Conductivity or TDS solutions. Calibration with pH solutions should be checked twice a month. Calibration of ORP is not necessary (ref. calibration intervals table under Calibration Steps below). B. Rules for Calibration of the POOLPRO 1.
To bypass a calibration, simply press value as-is. to accept the present b. Leaving Calibration Pressing accepts calibration and exits CAL mode if there are no more steps. Calibration is complete when the “CAL” icon goes out. Pressing any measurement key during calibration cancels changes not yet accepted and exits calibration mode. Leaving pH after the 2nd buffer results in the same gain being entered in place of the 3rd buffer. 2.
standard’s value (7032 > 7000) or hold a key down to scroll rapidly through the reading. e. Press once to confirm new value and end the calibration sequence for this particular solution type. If another solution type is also to be measured, change solution type now and repeat this procedure. 2.
1. Ensure pH protective cap is secure to avoid contamination. 2. Install the cell extender by pushing the base of the cell extender into the conductivity cell until it is fully seated. 3. Rinse the conductivity cell cup and cell extender 3 times with Alkalinity Standard 100PPM. 4. Refill cell cup and cell extender with Alkalinity Standard 100PPM. 5. Insert T-plunger into open cell extender until the “T” rests flush on the lip of the cell extender.
10. Using the pipette, add 100 µL of Reagent: A1, close the cell extender cap securely, then agitate and hold. Repeat as prompted. “PrES CAL” will display. 11. Press CAL to advance to the next titration point. “Add” alternating with “A1” displays; then “AGit t2” alternating with “HOLd” displays. 12. Tap the cell extender cap to dispel any solution clinging to the cap back into the cell. Carefully open the cell extender cap so as not to spill any solution. 13.
4. Refill cell cup and cell extender with Hardness Standard 200PPM. 5. Insert T-plunger into open cell extender until the “T” rests flush on the lip of the cell extender. This will cause fluid beyond what is required for titration to overflow the cell extender. 6. Rotate the T-plunger from side to side, allowing the arms of the T-plunger to slide along the rim of the cell extender. 7. Carefully remove the T-plunger so as not to flick or spill remaining sample.
reduces any bicarbonate alkalinity in the sample and prepares it for titration. After 120 seconds, “Add” alternating with “H1 1” will display. (The “1” indicates the first addition of sodium hydroxide.) Then “AGit” alternating with “HOLd” will display. 13. Change the pipette tip. 14. Using the pipette, add 100µL of Reagent H1 to the cell, close the cell extender cap securely to prevent any solution from spilling out, then agitate and hold. Repeat as prompted. “PrES CAL” will display. 15. Press CAL.
and holding the PS9 as prompted, then pressing CAL as prompted. A hardness value will display when the titration measurement is complete. 24. Press CAL. The “CAL” icon will display. 25. Adjust the displayed value to “200” using UP or DOWN key. The PS9 will not allow you to scroll up or down to “200” if it is beyond ±10% of the reading. Ref. Total Return to Factory Settings “FAC SEL”, pg. 42 to reset the Hardness Calibration to the “FAC” setting along with all other calibrations. 26.
sensor. If the pH reading is above 8 with pH 7 buffer solution, the sensor well needs additional rinsing or the pH sensor is defective and needs to be replaced. 5. Press or until the display reads “7.00”. NOTE: Attempted calibration of >1 pH point from factory calibration will cause “FAC” to appear. This indicates the need for sensor replacement (ref. Troubleshooting pg. 50) or fresh buffer solution. The “FAC” internal electronic calibration is not intended to replace calibration with pH buffers.
NOTE: If the “Acd” and “bAS” indicators are blinking, the PS9 is indicating an error and needs either an acid or base solution present in the sensor well. 3. Rinse sensor well 3 times with acid or base buffer solution. 4. Refill sensor well again with same buffer solution. 5. Press or 6. Press to accept 2nd point of calibration. Now the until display agrees with buffer value. display indicates the next type of buffer to be used. Single point Gain Calibration is complete.
VIII. CALIBRATION INTERVALS There is no simple answer as to how often one should calibrate an instrument. The POOLPRO is designed to not require frequent recalibration. The most common sources of error were eliminated in the design, and there are no mechanical adjustments. Still, to ensure specified accuracy, any instrument must be checked against chemical standards occasionally. A.
4. For maximum accuracy, keep the pH sensor cap on tight so that no fluid washes into the conductivity cell. 1. D. pH and ORP/Free Chlorine Practices to Maintain Calibration Keep the sensor wet with Myron L Storage Solution. 2. Rinse away caustic solutions immediately after use. ORP calibration solutions are caustic, and ±5% is considered very accurate.
(the temperature display alternates between temperature recorded and location number). 4. Press to display time and date stamp. 5. Press any measurement key to leave memory recall or allow to automatically turn off. C. Clearing a Record/Memory Clear After recalling a certain record location, press and HOLD to clear that memory. This space will be the place for the next memory record, unless you scroll to another empty position before ending the recall sequence.
X. TIME and DATE The Time and Date may easily be changed as you travel. A. Setting TIME Time is always displayed in 24 hour time. Example shown in Figure 11, 16:05 equals 4:05 PM. 1. Press 2. Press . until the time is displayed (scrolling through stored readings, “PC OFF”, and “CLr ALL” to time, e.g., “16:05”). 3. Press to initiate. “CAL” will be displayed along with the time (see Figure 8). Figure 8 4. Press or to change the time. 5. Press to accept the change (new time). B.
1. Press 2. Press . repeatedly until the date is displayed (scrolling through stored readings, “PC OFF”, “CLr ALL” and time to the date, e.g., “01.25 12” (Figure 9), January 25, 2012). 3. Press to initiate. “CAL” will be displayed along with the YEAR (see Figure 10). CAL Figure 10 4. Press or to change the YEAR. 5. Press to accept the change (new year). 6. Press or 7. Press to accept the change (new month), (see Figure 11). to change the month. CAL Figure 11 8. Press the 9.
CAL Figure 12 C. DATE FORMAT “US & International (Int)” 1. Press . 2. Press repeatedly until the format is displayed (scrolling 3. Press to change. Display will now indicate other format through stored readings, “PC OFF”, “CLr ALL”, time and date to date format). (see Figures 13 & 14). Figure 14 Figure 13 4. Press any measurement key or allow to automatically turn off. XI. TEMPERATURE FORMAT “Centigrade & Fahrenheit” 1. Press 2. Press to display the stored memory records. 3.
Figure 16 Figure 15 4. Press to switch units. 5. Press to accept unit preference for all temperature readings. NOTE: Tempco will still be shown in %/°C. XII. TOTAL RETURN to FACTORY SETTINGS “FAC SEL” There may come a time when it would be desirable to quickly reset all the recorded calibration values in the instrument back to the factory settings.
XIII. CELL CHECK The cell check verifies the cleanliness of the conductivity/MIN/ SALT/TDS sensor. In normal use the cell may become dirty or coated and require cleaning. If the display is showing “.00” when the cell cup is dry, the sensor is probably clean. No matter what a manufacturer claims, a sensor can and will become contaminated or coated and, therefore, require cleaning. A true 4-wire sensor, as in the POOLPRO, helps to mitigate contamination, but NO sensor is 100% immune. 1. Press . 2.
2. Press to display the stored memory records. 3. Press repeatedly until you pass the “CELL ch” location. The display will show “Auto oFF” (see Figure 21). Figure 21 4. Press to initiate. “CAL” will be displayed along with “15 SEC” or current Auto oFF value (see Figure 22). Figure 22 5. Press or to change the amount of time (see Figure 23). Maximum time of 75 seconds is shown. Figure 23 6. 44 Press to accept the change (new time).
XV. bluDock™ Wireless Data Transfer INSTRUCTIONS NOTE: Bluetooth® is a registered trademark of Bluetooth SIG. The bluDock Bluetooth module is a registered Bluetooth device. Requires Myron L bluDock™ accessory package, Model # BLUDOCK. Package includes POOLPRO hardware modification that allows the PS9 to communicate wirelessly with a personal computer configured for wireless device communication.
Figure 24 3. Then press the 25). key. “PC On” will be displayed (see Figure Figure 25 NOTE: “PC Ini” may momentarily be displayed while initializing (see Figure 26). Figure 26 4. Add bluDock to your Bluetooth devices per your operating system procedure. The bluDock device passkey is 1234. 5. After pairing, note the number of the COM port assigned by the computer. In Windows XP, note the number of the outgoing COM port assigned by the computer.
noted (first time only). This is the outgoing COM port on Windows XP. 3. In the U2CI application, click on the data download button. A data transfer bar will appear while the data is being downloaded. Once downloaded, the data may be manipulated, printed or stored within the Myron L U2CI application, or the data may be exported to another more powerful spreadsheet, such as Excel‡.
Open instrument carefully. Carefully detach battery from circuit board. Replace with 9 Volt alkaline battery. Replace bottom, ensuring the sealing gasket is installed in the groove of the top half of case. Re-install screws, tighten evenly and securely. NOTE: Because of nonvolatile EEPROM circuitry, all data stored in memory and all calibration settings are protected even during power loss or battery replacement.
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.
XVII. 50 TROUBLESHOOTING CHART Symptom Possible Cause No display, even though measurement key pressed Battery weak or not connected. Inaccurate pH readings 1. pH calibration needed. Ref. pH Cal., pg. 33. 2. Cross-contamination from residual pH buffers or samples in sensor well. 3. Calibration with expired pH buffers. No response to pH changes Sensor bulb is cracked or an electromechanical short caused by an internal crack. Will not adjust down to pH 7 pH/ORP sensor has lost KCl.
Corrective Action Check connections or replace battery. Ref. Battery Replacement, pg. 47. 1. Recalibrate instrument. 2. Thoroughly rinse sensor well. 3. Recalibrate using fresh buffers. Ref. pH Buffer Solutions, pg. 53. Replace pH/ORP sensor. Ref. Replacement pH/ORP Sensor, pg. 54. Clean and rejuvenate sensor (ref. Cleaning Sensors, pg. 48) and recalibrate. If no improvement, replace pH/ORP sensor (ref. Replacement pH/ORP Sensor, pg. 58). Clean and rejuvenate sensor (ref. Cleaning Sensors, pg.
XVIII. ACCESSORIES NOTE: MSDSs are available on the Myron L website for all solutions: http://www.myronl.com/main/Material_Safety_DS_DL.htm A. Conductivity/TDS Standard Solutions Your POOLPRO has been factory calibrated with the appropriate Myron L Company NIST traceable KCl, NaCl, and our own 442™ standard solutions.
2. Hardness Standard Solution HARD(CaCl2)-200 solution is a solution of calcium chloride (CaCl2) equivalent to 200 ppm calcium carbonate that is used for the hardness calibration: Order HARD-200. C. Titration Reagent Solutions Titration reagents are required for all conductometric titrations — alkalinity, hardness and LSI. LSI titrations require both alkalinity and hardness reagents. Reagents are available in 2 oz. and quarts/liters. 1.
G. Soft Protective Carry Cases Padded Nylon carrying case features a belt clip for hands-free mobility. Two colors to choose from: Blue - Model #: UCC Desert Tan - Model #: UCCDT H. Hard Protective Carry Cases Large, foam-lined case without UMIII PS9 includes the 100 µL pipette, 12 disposable pipette tips, 3 buffers (pH 4, 7, and 10), pH/ORP sensor storage solution, ORP Conditioner solution, reagents A1, C1, H1, H2, H3, and standard solutions, KCI-7000, 442-3000, ALK-100 and HARD200.
method that ignores fill level, electrolysis, electrode characteristics, etc., and features a microprocessor to perform temperature compensation. In simpler instruments, conductivity values are usually assigned an average correction similar to that of KCl solutions for correction to 25°C. The correction to an equivalent KCl solution is a standard set by chemists that standardizes the measurements and allows calibration with precise KCl solutions.
Using a 442 correction of 10 (degrees below 25) x 1.68% indicates the solution is reading 16.8% low. For correction, dividing by (.832) yields 1082 microsiemens as a compensated reading. A KCl correction of 10 (degrees below 25) x 1.9% indicates the solution is reading 19% low. Dividing by (.81) yields 1111 microsiemens for a compensated reading. The difference is 29 out of 1082 = 2.7%. D.
Clearly, the solution characteristics should be chosen to truly represent the actual water under test for rated accuracy of ±1%. Many industrial applications have historically used relative measurements seeking a number to indicate a certain setpoint or minimum concentration or trend. The POOLPRO gives the user the capability to collect data in “KCl conductivity units” to compare to older published data, in terms of NaCl or 442, or as appropriate.
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.
XXII. pH and ORP/Free Chlorine A. pH 1. pH as an Indicator 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.
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 28 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.
5. Sources of Error The basics are presented in pH and ORP/FREE CHLORINE, pg. 59. a. Reference Junction 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 POOLPRO PS9 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.
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 POOLPRO 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 The basics are presented in pH and ORP/Free Chlorine, pg.
disregards the fact that some chlorine species are better or worse sanitizers than others. The Myron L Company PS9 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 POOLPRO’s FCE feature provides the best reading-to-reading picture of the rise and fall in sanitizing effectivity of free available chlorine.
variables used in the calculation to analyze the effect of the change on water balance. The LSI titration function generates an accurate saturation index value that indicates the state of the system at the time the calculation is made. C. Hardness Units NOTE: The PS9 MUST be in the hardness function or the hardness screen (“Hrd”) in LSI Calculator or LSI Titration mode for hardness unit preference selection.
XXV. GLOSSARY Anions Negatively charged ions. See Solution Characteristics, pg. 57. Algorithm A procedure for solving a mathematical problem. See Temperature Compensation (Tempco) and TDS Derivation, pg. 58. FAC Free Available Chlorine. The amount of chlorine that remains active in solution and is available for ongoing disinfection. See Free Chlorine as an Indicator, pg. 62.
High Performance Features: • Accuracy of ±1% of READING ±.
Myron L COMPANY 2450 Impala Drive Carlsbad, CA 92010-7226 USA Tel: +1-760-438-2021 Fax: +1-760-931-9189 E-Mail: info@myronl.com techquestions@myronl.com www.myronl.
