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Thread: Initial shock to get CYA up- Is pool calculator correct?

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    Initial shock to get CYA up- Is pool calculator correct?

    I just filled my 1800 gallon vinyl pool with city water. FC is 0 (of course). Pool calculator says to add 24 oz of dichlor to get CYA to 50, but that adding this much dichlor will raise FC to over 50! Is this correct/safe? (Small pool, but I want CYA on high side because so many kids come over and splash a lot of water out that we have to replace. So I thought I'd start with high CYA.) How much dichlor should I add to get CYA up to a smart target from 0? And I think I remember from last summer that I don't add it all at once?

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    freqz's Avatar
    Join Date
    Sep 2013
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    Dallas, TX
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    Re: Initial shock to get CYA up- Is pool calculator correct?

    Sounds about right...~1ppm FC per ppm CYA added with that stuff.

    You could add 3-4 oz or so every time the pool needs to be fed chlorine until you hit your CYA target (or you could just add solid CYA.)
    25000 gal in ground plaster. '79 vintage. Cartridge filter.

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    JasonLion's Avatar
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    May 2007
    Location
    Silver Spring, MD
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    37,879

    Re: Initial shock to get CYA up- Is pool calculator correct?

    Yea, you don't want to raise CYA with dichlor all at once. I suggest adding the dichlor in four or five steps, one a day.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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