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Thread: Taylor Sodium Chloride Test (K-1766)

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    Taylor Sodium Chloride Test (K-1766)

    Hello,
    I bought the Taylor Salt Water tester because my SWG is on the fritz. I tested yesterday and it read about 3,600. Today, I had the PB come to check my SWG and he used my tester to check the level and he got 3,000 and we tested twice. I just went and tested and I got 3,600. I'm getting a lot of variability here. The only thing I can think of is the 3,600 were done when the pool filter was off for a few hours. The 3,000 results were when the pump was on and already running for about 7 hours. Any other or known causes?
    Thanks,
    Doug
    13,500 Gallon Gunite Aggregate Finish, DE, SWG, 2.0 HP pump, 1.0 HP pump for 3 Sheer Descents

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    JoyfulNoise's Avatar
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    Re: Taylor Sodium Chloride Test (K-1766)

    Please clarify, are you saying the Taylor test was giving you weird results? Or your SWG?

    For the test, it is best to use a speed stir to do the test as it free's you up from having to hand swirl. Also, one person should do the test, that's it. Different people will squeeze the bottle differently and that can cause variation. Also, the test is over as soon as you get the first permanent change from straw yellow to brick red. As soon as the red color holds, you stop. Many people keep adding drops trying to get the darkest red possible and that is not correct. As you get close to the end point, the yellow solution will "flash" red when you add a drop of titrant but will then revert back to yellow. You stop the test as soon as the solution becomes permanently red and doesn't go back to yellow. That is often a lighter color red than if you keep adding drops.

    Also, if you want a more accurate read, simply use a 20mL water sample. Then, the titrant precision is 100ppm/drop.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    bmoreswim's Avatar
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    Taylor Sodium Chloride Test (K-1766)

    Just testing variability. Your tests are consistent and so are his. Salt doesn't change after it's mixed. No big deal. You know the rough range. It's not an exact requirement. What is your goal in relation to getting the SWCG working?

    If you are following Joyful's procedure, I'd believe your results before his.
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    Re: Taylor Sodium Chloride Test (K-1766)

    Let me be clear. When I say I tested, I tested using the Taylor salt tester. The pool builder (PB) also used MY Taylor salt tester. I'm lost as to how he and I on the same kit got such different results.

    I just went to two different stores and they tested my salt on there devices both at 3,000. So, this agrees with the PB results who got 3,000 with my Taylor tester. I used the same water sample that I took to the pool store and I got 3,600 on the Taylor......tested twice. So, I am frustrated with the Taylor salt test on the inconsistency.....although I see consistency between my tests and the PB's....which are very different readings and this should not be. I'd expect maybe a drop off between two different people, but not 3.

    What I am preparing for is when the PB comes back and replaces my jandy aqua pure circuit board. They will need to set the salt level on the system. I'd like it as accurate as possible.

    - - - Updated - - -

    Also.....when I test, my end point is the first drop that maintains a pinkish water after swirling. I don't continue adding drops after this.....I'm done.
    13,500 Gallon Gunite Aggregate Finish, DE, SWG, 2.0 HP pump, 1.0 HP pump for 3 Sheer Descents

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    Mod Squad jblizzle's Avatar
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    Re: Taylor Sodium Chloride Test (K-1766)

    Are you and them swirling the same? SpeedStir helps.

    Although I think you are too worried over something that really does not matter.
    Jason, TFP Moderator
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    JoyfulNoise's Avatar
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    Re: Taylor Sodium Chloride Test (K-1766)

    Did you literally stand next to your PB while he was doing the test and watch him do it? Because I can guarantee that two people will do the test different enough to cause as much variation as you are seeing. PBs are not known for their chemistry skills or for being patient and precise.

    Digital testers can be highly inaccurate unless they are properly calibrated because they don't measure salt, they measure conductivity and INFERE the salt level from there.

    If you want a more accurate test, then use a 40mL water sample and you'll get 50ppm/drop from the titration. I would suggest you reread my post on how to determine the proper end point and use a SpeedStir to do the test. Your results will be the right one.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    Re: Taylor Sodium Chloride Test (K-1766)

    JoyfulNoise,

    Yes, I read your post and all of the others. Yes, I literally stood next to him. He spent at least 7 "pours" to get to the 10 ml line. Yes, I am testing correctly and know when the endpoint is......it's as soon as a drop holds a salmon red color.

    I just did two more tests. My wife got 4,000 and I got 3,600. I watched her do the entire test and verified she was spot on the 10 ml line. This kit is not very reliable.

    I've always thought about getting a speedstir......I've always wanted one just because I like gadgets.

    You are saying two things however......you are saying in your first post to test with 20 ml line and your last is saying 40 ml. Why is that? Is it the more water, the more accuarate?

    I looked up that speedstir. That will work with a tube tester. What would work with the K-2006 style test tube? Would like to just get one type of stirrer for all test kits.

    Thanks,
    Doug

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    MARCO...polo's Avatar
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    Re: Taylor Sodium Chloride Test (K-1766)

    I remember reading something about this awhile back and if memory serves correctly the accuracy rating for this test was 10% + 1 drop. So on a result of 3600, 360 + 200 = 560 variance. No, it does not seem accurate but the "experts" say it is. Bottom line, if your SWG is happy so should you be.
    13,000 gal.Peanut shaped IG Plaster (med. gray) w/ 7' raised spa. ALL Pentair: Intelliflow 3hp VS, Cartridge filter, 400,000 btu heater, 2.0hp spa motor, Easy Touch control panel & is4 spa side switch, Intellichlor 40C SWG, Paramount PV3 In Floor cleaning system, spa spillway and two sheer descents. Solar: 10 FAFCO panels 1.5hp booster. Testt kits: K-2006 & K1766 (Chloride/Salt) Fill date August 15, 2114.

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    Re: Taylor Sodium Chloride Test (K-1766)

    Quote Originally Posted by dubele View Post
    JoyfulNoise,

    Yes, I read your post and all of the others. Yes, I literally stood next to him. He spent at least 7 "pours" to get to the 10 ml line. Yes, I am testing correctly and know when the endpoint is......it's as soon as a drop holds a salmon red color.

    I just did two more tests. My wife got 4,000 and I got 3,600. I watched her do the entire test and verified she was spot on the 10 ml line. This kit is not very reliable.

    I've always thought about getting a speedstir......I've always wanted one just because I like gadgets.

    You are saying two things however......you are saying in your first post to test with 20 ml line and your last is saying 40 ml. Why is that? Is it the more water, the more accuarate?

    I looked up that speedstir. That will work with a tube tester. What would work with the K-2006 style test tube? Would like to just get one type of stirrer for all test kits.

    Thanks,
    Doug

    The test is accurate. In fact it the only accurate test for chloride levels because it is actually using a chemical reaction to measure the chloride and there are no chemical interferences. This test has been around for well over a century (look up Mohr's Argentometric Method) and was developed back in the days when people had to do quantitative chemistry without the aid (or crutch) or electronic devices. Every other method of salt determination - TDS meters, capillarity strips, or hydrometers - use a proxy to "measure" the salt levels. Those proxies (electrical conductivity, capillarity, specific gravity) are much, much more subjective to interpretation, environmental influence and human error.

    What you are seeing in the tests variation are variations in the humans doing it. The dropper bottles are good at forming 40 micro-liter droplets but any variation in squeeze pressure and rate can cause droplet volume variations. In fact, when creating droplets, you use a constant pressure; you should not ever do squeeze, release, squeeze, release, etc., because the changes in back pressure inside the dropper bottle can vary droplet size. This is why you, your PB and your wife can all get slightly different results - you are all measuring the sample volume slightly differently (most people don't understand the concept of a water meniscus and where the proper levels is) and you are all squeezing the droplet bottle differently.

    Yes, you should get a SpeedStir as it makes testing much more uniform. You should also consider getting a SampleSizer. The SampleSizer allows you to get very exact and repeatable sample volume sizes using the standard Taylor test tube. Trying to accurately measure 10mL can be difficult and the SampleSizer makes that process very repeatable.

    As for sample volume and titrant precision, yes, the larger the water sample, the higher the degree of precision. It's just simply volume/concnetration ratios. If the titrant produces a 200ppm/drop precision in a 10mL sample, then a 20mL water sample will have a precision of 200 * (10/20) = 100 ppm/drop. A 25mL sample will have a 200 * (10/25) = 80ppm/drop precision and a 40mL water sample will have a 200 * (10/40) = 50ppm/drop. The titrant is a fixed concentration so it reacts with a specific number of moles of chloride ion. The larger the water sample, the more total moles of chloride present and thus the greater number of drops needed. Since the concentrations are all fixed and the volume of titrant delivered in each droplet is fixed, then the volume ratios determine the precision of the test. This is true in many of the other tests as well - if you double the water sample volume, you half the precision of the test (e.g., a 50mL water sample with the TA test will give a 5ppm/drop precision of the R-0009 titrant). There are limitations to how large or small a sample you can test, but simply doubling or halving the test water volumes is usually not that hard.

    At the end of the day, it's up to you to trust your results. As TFP always says, your results, and yours alone, are the only ones that matter. You are the only person that cares about your pool water and it is your testing that is the most accurate. As an aside, I have been doing this test for years, and it has never failed to produce repeatable and accurate results. Many others on here use this test and they will all tell you the same thing.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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    JoyfulNoise's Avatar
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    Re: Taylor Sodium Chloride Test (K-1766)

    Quote Originally Posted by MARCO...polo View Post
    I remember reading something about this awhile back and if memory serves correctly the accuracy rating for this test was 10% + 1 drop. So on a result of 3600, 360 + 200 = 560 variance. No, it does not seem accurate but the "experts" say it is. Bottom line, if your SWG is happy so should you be.
    Not correct.

    The stated error/tolerance of the test is +/-200ppm. It's not +/-10%.

    The accuracy of the test (difference between true and measured value) can be a little higher and closer to 10% because the sample size is small. One can easily get better accuracy by simply increasing the sample size as I stated above.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

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