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Thread: crystal clear pool cya 0

  1. Back To Top    #1

    Join Date
    May 2010
    Enfield CT

    crystal clear pool cya 0

    Hi just signed up and received my tf100 kit in mail . I have a 18x40 IG Hayward DE vinyl pool
    opened it last sunday to a green swamp. I hit it w/ my leftover from last season cal hypo for the last week and have inline feeder w/ 3" trichlor tabs running when pump does
    pump run time 18 hours a day . backwashed it at least 4 times and pressure is 21 up from 15 at start now.
    FC 17.5 ? pH 6.8, TA 80 CH 300 CYA 0 vial was full and just still fuzzy black dot
    pool calc is not saying to add anything. remove 13% of water to reduce hardness
    What about CYA level of 0 ?
    Still have 20 tabs left and 5 lbs of cal hypo . went out and bought clorox and arm & hammer
    18X40 IG, Vinyl, DE, Mesh Safety Cover,

  2. Back To Top    #2

    Join Date
    Jan 2009
    Cupertino, CA

    Re: crystal clear pool cya 0

    Welcome to TFP!

    Your CH 300 is okay for now, but stop using the cal-hypo (adds 7ppm CH for every 10ppm FC). CH should drop slowly over time as you replace water from splashout or backwashing. Nothing to be worried about at this stage, certainly not a reason to replace water.

    I'd say save the remaining tabs for vacations and go buy some real CYA. People seem to like the Walmart version, or go to the pool store; make sure the ingredients show at least 90% Cyanuric acid.

    Ignore the pH reading when your FC is so high. If you catch a sample that's down in the FC 10-15 range, you can look at pH again; it will still be off some, but not a huge amount.

    Let us know how it goes; I'm sure we are about to chalk up another success story!
    BBB "Intermediate Swimmer"
    IG plaster pool 18.5K gal, Hayward Pro-Grid DE filter, 3/4 HP Hydramax II; Polaris 380, 3/4 HP booster
    AG spa 325 gal, probably Sundance of some kind
    Water testing instructions on one page

  3. Back To Top    #3

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: crystal clear pool cya 0

    The pH skew at high FC is usually to the high side.....implying that your pH could be even lower.

    I would suggest letting the sun burn off the FC (don't add the cYA just yet) until the FC gets down below 10ppm. Then test pH again and prepare to bring it up to around 7.2-7.6 with 20 mule tem borax.

    Do not let the FC stay below 7.0 for an extended period.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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