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Thread: Where is my CYA?

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    Join Date
    Oct 2015
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    mesa, az
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    Where is my CYA?

    I was fighting high CYA last year and, through draining, got it under control. Thanks to this forum, I knew what to do. (Drain and fill and drain again.)

    Now I have the opposite problem. I am getting no / barely detectable CYA reading on my test. The first time I noticed the low level, I put in two pounds of HTC brand from Wally World with the sock method. Waited a week. No change. Put in the other two pounds, waited a week, no change. About a month later, put in four pounds. Waited a week. No change. Went to the pool supply store (I know, blasphemy) and tried their brand. No change.

    I thought maybe my reagent was too old, so I got some fresh. Still no reading. All other chemicals are balanced, but I'm burning through chlorine. Any advice anyone can give to me would be greatly appreciated.
    13000 gallon in ground cement diving pool,
    Triton II sand filter
    plaster/cement

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    kcindc's Avatar
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    Re: Where is my CYA?

    What test kit are you using to test CYA?

    How did you add the CYA to the pool?

    Are you following the test instructions as stated here: Extended Test Kit Directions

    "CYA - Cyanuric Acid

    Fill the mixing bottle to the lower mark with pool water. The lower mark may be labeled as 7 ml, 15 ml, or not labeled.
    If the pool water is below 70 degrees, allow the water sample to warm up to room temperature before continuing.
    Continue filling to the upper mark with R-0013. The upper mark may be labeled as 14 ml, or not labeled, or there may not be a mark and you fill to the base of the neck of the bottle.
    Cap and then shake the mixing bottle for 30 seconds.
    Stand outdoors with your back to the sun and hold the view tube at about waist level. If sunlight is not available, find the brightest artificial light you can.
    Looking down into the view tube, slowly pour the mixture from the mixing bottle into the view tube.
    Continue pouring until all traces of the black dot at the bottom of the view tube completely disappear, even after you stare at it for several seconds, or you fill the view tube.
    Reading the result:
    If the view tube is completely full, and you can still see the black dot clearly, your CYA level is zero.
    If the view tube is completely full and the black dot is only partially obscured, your CYA level is above zero but lower than the lowest level your test kit can measure (20 or 30 ppm).
    If the tube is not completely full, look at the scale on the side of the view tube. The labeled mark closest to the liquid level indicates your CYA level.
    If your CYA level is 90 or higher, repeat the test adjusting the procedure as follows:
    Fill the mixing bottle to the lower mark with pool water.
    Continue filling the mixing bottle to the upper mark with tap water.
    Shake briefly to mix.
    Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
    Continue the test normally from step 3, but multiply the final result by two.


    Notes
    If you are not confident in your reading, you can pour the solution from the view tube back into the mixing bottle and then try filling the view tube again. You can repeat this portion of the test over and over again for several minutes without affecting the test results.
    This page at Taylor Technologies has photographs which show what the view tube looks like when the test is complete.
    Very rarely, cloudy or murky water can affect the CYA test. To check for this, fill the view tube with straight pool water. If you can still see the black dot clearly, the cloudy/murky water is not affecting the test result.
    View tubes and mixing bottles come in two common sizes. One set requires 7 ml each of pool water and reagent, and reads CYA levels down to 30. The other set uses 15 ml each of pool water and reagent, and reads CYA levels down to 20.
    It is also possible to get a tube with a sliding black dot, Taylor 4088, so that you move the black dot up and down in the sample, instead of pouring the sample into the view tube.
    If you are using the large view tube and know that your CYA level is at least 50, you can use half as much pool water and half as much R-0013 to save on reagent.
    R-0013 contains melamine, which binds to cyanuric acid, forming the white precipitate which turns the sample cloudy.
    The precision of the test, when done correctly, is around plus or minus 15 for levels up to 90 and plus or minus 30 for levels between 100 and 200. Novices often have problems reading the test correctly, and tend to get higher than actual readings."
    Last edited by kcindc; 07-15-2016 at 10:37 AM. Reason: Ask another question
    Karen
    33K IG w spa plaster, Pentair 1HP Whisperflo, DE Filter, SWG CircuPool RJ-60, Dolphin Triton Plus, Raypak Dig 336K BTU, TF-100.
    Pool Math Chlorine / CYA Chart SLAM - Shock Level And Maintain
    2017 replaster/retile

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    duraleigh's Avatar
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    Re: Where is my CYA?

    In that pool you have introduced enough CYA to raise it to 70 ppm. You don't say how much you put in from the pool store so add that to you dosage and you are too high once again. With your conditions CYA simply does not go away. The only possibility is you have a very sizable water leak and an autofill and have not noticed that leak.

    You say you are "burning through chlorine" but that doesn't help.....how much ppm are you burning daily?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    mesa, az
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    Re: Where is my CYA?

    Two gallons every three or four days.
    13000 gallon in ground cement diving pool,
    Triton II sand filter
    plaster/cement

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    Re: Where is my CYA?

    Well, that's about 13 ppm daily.....wa-a-a-ay excessive.

    I think you need to get another CYA test somewhere else. I would normally never suggest ANY pool store testing but unless you have a neighbor that can test for CYA, then I think you need to get it done at a pool store. Let us know the results.

    If it's not a testing error and there really is no CYA in your pool, you have been buying the wrong product. I realize that is VERY far-fetched but we are sorta' running out of possibilities.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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