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Thread: CYA question

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    Join Date
    Aug 2010
    Lake Jackson, TX

    CYA question

    My CYA is running high, 100+, so I am prepping for a drain refill soon once I get some equipment problems sorted out. I had a discussion with a pool store clerk, hence posing the question here, where he stated that the CYA was mostly at the top of the water and that I should therefore pump the water from the top of the pool when trying to lower CYA. So, is this pool store babble or is there anything to it? I have not seen anything like that on the forum.

    On a related note, I notice a lot of people having trouble reading the CYA when it's over the 100 mark on the tube, myself included. The scale is logaritmic so it's not an easy read. Sorry if that is obvious to most, I just hadn't seen any cautions regarding guestamating numbers over the 100 mark.
    25000 gal IG gunite plaster. Built in spa, built 1984.
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  2. Back To Top    #2

    Join Date
    May 2011
    lebanon tn

    Re: CYA question

    most test kits don't even have readings over 100, so 100 really means 100+ AND no way of knowing how much +++++
    If your pool is circulating, pump/filter online, then the CYA is fairly well mixed- add water opposite side and top/bottom from where you fill if doing at same time; if not, drain what you can (don't overdo the draining, can cause other problems!) then fill and recirc a few hours before testing again!
    24ft x 52in AGP 18000 gal
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  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: CYA question

    Once it is mixed in, CYA is very throughly spread throughout the water and stays that way. It does not accumulate more at one depth than at any other.

    Don't try to guess the level over 100 based on a standard test. You will be way off. What you can do is to do the test with dilution. Mix equal parts of pool water and tap water together, measure the CYA level of that, and multiply the result by two. The results will be less precise, but they will give you an idea if your CYA level really is around 100, or more like 200+.
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  4. Back To Top    #4

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: CYA question

    It is, in fact
    pool store babble
    Disregard it.

    I wouldn't even attempt to interpret anything over 100 on the CYA test. rather make a 50/50 pool water/tap water solution and multiply the results by two. It's not very accurate, but it will give you a rough idea.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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  5. Back To Top    #5
    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    East Texas

    Re: CYA question

    I'm sure glad the "Big Boys" weighed in on this assumption. That would make life Waaaaaaaaaaay too easy if the CYA stayed in the top say 1 foot of water or so.
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