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Thread: High CYA?? Low alkalinity?

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    High CYA?? Low alkalinity?

    We are first time pool owners and read all we can about pool chemistry, but we are relying heavily on our local pool store owner's expertise. I'm beginning to doubt her expertise, and need some help....

    We have been battling cloudy water. Each time, we take a sample into the pool store, we are told our alkalinity is low and to add baking soda, which we do, but as soon as it clears up, the TA starts to decline and we start all over again. After opening our pool, we had difficulty maintaining proper chlorine levels, so it was recommended we add stabilizer, which we did. We have an automatic chlorinator, which contains trichlor pucks. Our latest water testing, indicated a CYA of 94, which seems high (or maybe it's not??). I'm concerned with continuing to use the trichlor tablets for our chlorine source, for fear our CYA will continue to rise. Could the high CYA be contributing to the low alkalinity levels? If our CYA is considered high, should we discontinue use of the trichlor tablets until the CYA is lower?

    Here are our last two water sample readings: (We have a 26,000 gallon pool, with vinyl liner, DE filter, avg water temp 82 degrees F)
    Saturation index: -0.1
    CYA: 94
    Total Chlorine: 3.4
    Free Chlorine: 3.3
    pH: 7.8
    TA: 121
    Adjusted TA: 93

    Saturation index: -0.8
    CYA: 50
    Total Chlorine: 7.5
    Free Chlorine: 6.5
    pH: 7.1
    TA: 99
    Adjusted TA: 84


  2. Back To Top    #2

    Join Date
    Jul 2009
    Fort Wayne, IN

    Re: High CYA?? Low alkalinity?

    yes, your CYA is too high and the only way to lower it is to drain some of the water. Most people here rarely use pucks. Most of us only use Bleach. Someone with more experience will chime in soon.

    Welcome to TFP and congratulations on making it out of the pool store alive!
    Theresa and/or Gary

    Complete DIY: 20x40' rectangle. Resin walls, vinyl lined. 33000 gallons. Full width steps. 8' deep. Diving board, slide. Hayward pro series super pump, sand filter. Raypack 336K BTU heater. Main drain, 2 skimmers, 3 returns, 2 amerilite lights with quick change lens Aquamatic auto cover and a partridge in a pear tree.
    Breaking our backs in the hopes that one of our six kids will care for us when we are old ;)

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    Join Date
    Jun 2012
    Howell, NJ

    Re: High CYA?? Low alkalinity?

    Using those pucks, your CYA will continue to rise, and your pH and TA will continue to fall. What I recommend is to get yourself a proper test kit (linked to in my signature) and, since your pool is cloudy, follow the SLAM process (also linked to in my signature, as the shock process.)
    7 year old ~13,500 gal 24' AGP with 1.5 hp Proline pump, 150 sqft Pleatco cartridge, filled with well water with pH of about 4.5.
    Wanda the Whale pool vacuum, home made heater, Taylor K-2006
    Cloudy Pool? 1) Order test kit. 2) Follow SLAM
    New to TFPC? Read Pool School a few times, then post questions. PoolMath will help with chemical additions.

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    Re: High CYA?? Low alkalinity?

    Thank you! I will definitely be ordering my own test kit and investing in some bleach.

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    Smykowski's Avatar
    Join Date
    Sep 2011
    Gurnee, IL (North Suburban Chi-town)

    Re: High CYA?? Low alkalinity?

    Welcome to the forum. Spend your time waiting on the kit in Pool School. Lots of info there, and it will take some time to digest. Read it several times, and you will be ready to tackle the pool when your kit arrives.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
    The most important article on this site - The ABCs of Pool Water Chemistry

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