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Thread: Use trichlor in spa to raise CYA?

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    Use trichlor in spa to raise CYA?

    Split by moderator from HERE. jblizzle

    is it possible to use a triclor tablet in spa to raise cya??
    24,000 gallon ig fiberglass pool
    1 hp hayward pump
    hayward sand filter (250 lb)
    madisonville, ky

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    Swampwoman's Avatar
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    Re: How do I use Chlorine in my Spa (or pool)?

    ^I wouldn't use the regular 8 ounce one...it would take you until xmas for the chlorine to drop to a use-able level. You could, however, use one of the 1" tablets they sell in the summers for folks with small temporary pools -- which I have done to add CYA. It still "superchlorinates" for my small tub -- and ya gotta watch that it doesn't push the ph down TOO far. You can get a lot more precise if you just use dichlor instead.
    In ground extended Grecian, 22,000 gal, Hayward 220t sand filter, vinyl liner, dolphin m4 supreme.
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    Re: How do I use Chlorine in my Spa (or pool)?

    In 350 gallons, a 1" 1/2-ounce Trichlor tablet will increase FC by 9.8 ppm, increase CYA by 5.9 ppm, and lower the TA by 6.9 ppm. As for pH, that depends on your TA level and aeration, but worst-case at a TA of 50 ppm with no carbon dioxide outgassing it would lower the pH from 7.5 to 6.9 (after chlorine was used/consumed). So it's not a disaster if you use only a single tablet.

    As was mentioned, Dichlor is faster and easier to use and adds more CYA per FC. A 1/2 ounce of Dichlor will raise the FC by 5.9 ppm, the CYA by 5.4 ppm, lower the TA by 2.1 ppm, and the pH in my example would drop to only 7.2 ppm (after chlorine was used/consumed).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Swampwoman's Avatar
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    Re: How do I use Chlorine in my Spa (or pool)?

    See, if I wasn't so iPad-lazy in my answer I could have looked up chem geek's other posts with these excellent specifics and linked you to it to have saved him some time

    Sorry, chem geek, and thanks for specifying. I know it's much more helpful!
    In ground extended Grecian, 22,000 gal, Hayward 220t sand filter, vinyl liner, dolphin m4 supreme.
    If TFP has helped you, please click to SUPPORT TFP!
    Helpful Links:
    GET A TEST KIT Chlorine/CYA Chart How to SLAM About Metals & Stains

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