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Thread: Lowering CYA

  1. Back To Top    #1

    Join Date
    Oct 2010
    Houston, TX

    Lowering CYA

    Hi, my CYA is 160 due to trichlor tabs the previous owners used to use, and I would like to lower it. The pool is 18000 gallons or so, so I don't really want to drain half of it and refill.

    Will evaporation with subsequent refilling eventually do it? Does CYA even evaporate, or does it remain concentrated in the pool? And if it does evaporate, will this take way too long to lower CYA? Any other ideas on lowering CYA? Thanks
    15k gunite pool. Intelliflo VF. Autopilot SWG.
    2k separate spa with waterfall (ie: pain in the rear maintaining a separate body of water). 2HP Hayward Tristar pump.

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    dmanb2b's Avatar
    Join Date
    Apr 2009

    Re: Lowering CYA

    CYA does not evaporate. I does sometime degrade over the winter months and convert to ammonia, but unpredictably. Should you live in CA, NV or AZ reverse osmosis treatment may be an available option, otherwise you are looking at water replacement.
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

    Pool School, TFTestKits, Pool Calculator

  3. Back To Top    #3
    Richard320's Avatar
    Join Date
    Jan 2010
    San Dimas, CA (LA County)

    Re: Lowering CYA

    You can do it gradually, like I did: use pool water to water the lawn then refill the pool with fresh water. That also is how to get rid of excessive Calcium. It takes a loooooong time.

    I've been able to speed it up on the cheap by putting a flexible downspout extension so it goes in the pool. 1" of rain gets me about 3" in the pool. But then you also have to be around to monitor the water level and pump enough out without going so low you start sucking air in the skimmers
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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