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Thread: CYA Test Differences

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    CYA Test Differences

    This is kind of a weird thing. When I test my CYA with my Taylor K-2006 kit I get a high reading of 80. When I bring a sample to the local pool store they get a reading of 25. In the Taylor kit, I add solution until the dot on the bottom of the tube disappears. In the pool store test it has a black dot on a slide in a graduated cylinder which you can vary it's depth in the solution until it just disappears and read the CYA level from a scale on the slide.
    The solution in the Taylor kit is the same as the pool store. Both kits mix solution and water for the test media. In the Taylor kit, I mix 7 ml of water and 7 ml of solution for 30 seconds. In the pool kit, I add water to one mark, and solution to the next up and work the slide 5 times.
    They even gave me some new solution and their test tube. (for free) to take home and try. Results are still the same difference, even when using the new solution. What gives with the two different readings?
    My chemistry;
    Chlorine:1.8
    Ph:7.4
    Alkalinity: 80
    Ch: 300
    CYA: 25 or 80?
    Copper: 0.4 I have a copper/silver ionization system for algae control which works great and allows me to keep lower chlorine levels and still have pristine water.
    16x32 IG Vinyl pool. New liner 2007. Hayward 4820 DE filter, 1.5hp Pentair Whisperflow pump, Thomsen Tec copper/silver ionization system, Taylor K-2006 test kit. Polaris 9550 pool robot.

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    Mod Squad woodyp's Avatar
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    Re: CYA Test Differences

    Rule #1......"Trust your own testing". Welcome to the forum. You might read up on our suggestions of using that copper/silver system. Your FC is woefully low for your level of cya as well. See the chlorine/cya chart in Pool School.
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    Mod Squad tim5055's Avatar
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    Re: CYA Test Differences

    Yup, trust your testing. You care about your pool, the store cares about selling you stuff - the testing suffers due to many factors including poorly trained staff, trying to work too quickly or just outright dishonesty.

    As woodyp suggested, do some reading in the Pool School. This site exists to arm you with the tools to make informed decisions on caring for your pool.

    Welcome!
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: CYA Test Differences

    As I understand Taylor is 80 and pool store is 25.

    What do you get if you use the reagent from the Taylor kit and the pool store test tube?
    and
    Did the pool store recommend that you buy some CYA?
    IG under fir trees and one cherry surrounded by grass built in 1979, 30k, plaster, old Sta-Rite HRPB30, 4.9 sq.ft, 20 GPM/sq.ft., but with new glass, new (in 2012) 1 HP WhisperFlo one speed, new (in 2013) Rainbow tab chlorinator attached at the top, old Maxi-Flo Heat Exchanger MF-260, Burnham V7 oil heater 245 MBH, new (in 2012) Compool to Easytouch, Taylor K-2005 and TF-100.

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    Re: CYA Test Differences

    Thanks everyone for the responses and welcome. It's great to have such a helpful and knowledgeable group to bounce problems off of.

    A note about the tests. Except for the CYA level, my tests match the pool store readings almost exactly. I do trust my own testing, just can't figure the CYA difference.

    A note about the local pool store. The manager is more interested in helping her customers than selling stuff. A rarity and I feel lucky to have her in town. She gave me a gallon of the CYA test solution (I believe it's R0011 if memory serves me) and the test tube at no charge. I thought she might have been loaning it to me, but when I tried to return it to her, she wouldn't take it back or charge me for it. This is not the first time she has given me things for free. She has 20 years experience in owning, installing and maintaining pools, and frequently mentions looking online for a better price than in her store, like the filter grids which I found for a third of her price. It's good to have someone I can trust. She is at a loss as to why the CYA readings are different and has not tried to sell me anything to cure the problem. I like their test tube with the slide. It makes more sense to be able to vary the depth of the dot and be able to determine exactly where the dot appears or disappears.

    woodyp, I've been using the ionization system for about 6 years and always kept minimal levels of chlorine. Just enough to oxidize the residual contaminants. Water is always crystal clear and people always like the low levels of chlorine, especially those who have a sensitivity to it. I didn't take pool chemistry seriously until 2 years ago when I bought the Taylor kit from Amazon, based on recommendations from the pool store lady. My alkalinity is still high because I used to use baking soday to adjust the PH after every rainstorm. I will search TFP for ionizer advice. I saw posting for SWG ionizors, but nothing for the copper/silver.

    engrave, I have not used my reagent with their test tube, but now that you mention it, I will. Their tube takes much more of the reagent, hence her reason for giving me the gallon (for free).
    16x32 IG Vinyl pool. New liner 2007. Hayward 4820 DE filter, 1.5hp Pentair Whisperflow pump, Thomsen Tec copper/silver ionization system, Taylor K-2006 test kit. Polaris 9550 pool robot.

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    Mod Squad woodyp's Avatar
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    Re: CYA Test Differences

    Man............if it's working for you, then......"PARTY ON GARTH"! The CYA test to answer your question----------there is a big difference in testing done under flourescent lights vs. natural outside sunshine with the sun to your back.
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
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    Re: CYA Test Differences

    OK, so I've rerun the CYA tests as follows.

    Pool store test tube with their reagent
    Pool store test tube with my reagent
    Taylor kit with their reagent
    Taylor kit with my reagent.
    All done with same lighting in the same location.

    Still getting the same readings. Taylor 80 ppm. Pool store test tube 25 ppm.

    Since pool store analysis matches mine on all tests except CYA, I don't know which CYA test to trust. Seems I would need a third independent test, but where?
    16x32 IG Vinyl pool. New liner 2007. Hayward 4820 DE filter, 1.5hp Pentair Whisperflow pump, Thomsen Tec copper/silver ionization system, Taylor K-2006 test kit. Polaris 9550 pool robot.

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    nedchavez's Avatar
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    CYA Test Differences

    You could ask your pool person if she can get some R-7065 CYA Standard Solution.

    Or order some from tftestkits.net

    This standard should read 50 ppm CYA with whatever tester you use.

    If you do, please let us know what you find!
    16' x 32' IG vinyl liner w/ hopper bottom (12,500 gal), Single-speed 1 HP Sta-Rite pump, and 300# Cristal-Flo sand filter, TF-100 test kit

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    Re: CYA Test Differences

    is this a premixed solution for testing the test kits?
    16x32 IG Vinyl pool. New liner 2007. Hayward 4820 DE filter, 1.5hp Pentair Whisperflow pump, Thomsen Tec copper/silver ionization system, Taylor K-2006 test kit. Polaris 9550 pool robot.

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    Mod Squad tim5055's Avatar
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    Re: CYA Test Differences

    Quote Originally Posted by gadgetman9 View Post
    is this a premixed solution for testing the test kits?
    exactly. Premixed to show a 50 CYA
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: CYA Test Differences

    Quote Originally Posted by gadgetman9 View Post
    OK, so I've rerun the CYA tests as follows.

    Pool store test tube with their reagent
    Pool store test tube with my reagent
    Taylor kit with their reagent
    Taylor kit with my reagent.
    All done with same lighting in the same location.

    Still getting the same readings. Taylor 80 ppm. Pool store test tube 25 ppm.
    Thank you
    Helpful for me to know that the variance does not derive from the sample or the reagent.
    IG under fir trees and one cherry surrounded by grass built in 1979, 30k, plaster, old Sta-Rite HRPB30, 4.9 sq.ft, 20 GPM/sq.ft., but with new glass, new (in 2012) 1 HP WhisperFlo one speed, new (in 2013) Rainbow tab chlorinator attached at the top, old Maxi-Flo Heat Exchanger MF-260, Burnham V7 oil heater 245 MBH, new (in 2012) Compool to Easytouch, Taylor K-2005 and TF-100.

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    Re: CYA Test Differences

    Quote Originally Posted by nedchavez View Post
    You could ask your pool person if she can get some R-7065 CYA Standard Solution.

    Or order some from tftestkits.net

    This standard should read 50 ppm CYA with whatever tester you use.

    If you do, please let us know what you find!
    Ok, so I ordered the R-7065. Just to make sure, I use it straight and not mixed with pool water. I would use it as is to test the kit's accuracy, correct?
    16x32 IG Vinyl pool. New liner 2007. Hayward 4820 DE filter, 1.5hp Pentair Whisperflow pump, Thomsen Tec copper/silver ionization system, Taylor K-2006 test kit. Polaris 9550 pool robot.

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    nedchavez's Avatar
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    CYA Test Differences

    You are correct!

    EDIT: Sorry, bad info. See jblizzle below for correct info!
    16' x 32' IG vinyl liner w/ hopper bottom (12,500 gal), Single-speed 1 HP Sta-Rite pump, and 300# Cristal-Flo sand filter, TF-100 test kit

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    Mod Squad jblizzle's Avatar
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    Re: CYA Test Differences

    Well, almost. You add the standard solution instead of pool water and then add the normal CYA reagent to it. The reading should be 50ppm ... so you need to find the lighting and arm position that gives you a 50ppm reading.
    Jason, TFP Moderator
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    Re: CYA Test Differences

    I've had some good luck and not so good with my CYA testing both last year and this. This is quite worrisome.
    Thanks to searching the forum for help in perfecting my TF-100 testing techniques for CYA, I found a thread suggesting the standard solution.
    I should be receiving it today. However, I didn't think about the last part of jblizzle's post coming into play at all.
    It makes sense that the standard solution would only show at 50ppm when in the ideal lighting situation which would include arm/hand tilt or height.
    Finding that ideal lighting and so forth will tell you/me the ideal situation for an accurate reading using our pool water with the reagent.
    Thank you for this added info which I should have thought of but didn't.

    That's a, well DUH! on me.
    Thank you again!
    JoanC--Rome, GA
    18.5 x 41 Grecian IG Vinyl--34,000 Gallons
    Hayward S244T -Sand Filter - design flow rate 62GPM, Turnover 29,760 G/per 8hr
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    Presume pool built with house 1989. Owner since 2002.

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    Re: CYA Test Differences

    I find this quite interesting. Waiting to find out what happens.....
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