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Thread: CYA reading-it's way high!

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    CYA reading-it's way high!

    I'm just getting started with the BBB method and after obtaining a good quality a good quality test kit I have the following
    FC 2.0
    PH 7.4
    TA 140ppm
    Calcium 550 ppm
    CYA approx 400--really don't know off the scale just an extrapolation.

    Everything I have read the only way to lower the CYA is to drain and replace. The question I have is that by starting the BBB method and not using a stablizer will the CYA eventually come down byt slpash-out and evaperation replacement or should I do a drain and replace?

    Pete in San Antonio
    11K IG Gunite/325 Serires Hayward cartridge

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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD
    CYA will come down very slowly over time if you stop adding it. It your CYA level was 90, waiting for CYA to come down might be a reasonable strategy. If your CYA level is actually 400, waiting for CYA to come down will take years and years and there isn't any practical way to manage the pool in the mean time.

    You should get your CYA level under 100 by water replacement and then let it go down more slowly from there.
    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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    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    SW Indiana
    Evaporation won't affect CYA. Only splash out and water replacement. The CYA test is not linear, so extrapolation of the test is tough. You can try diluting the water sample with distilled water 50/50 or 25/75 and multiply accordingly to get a rough result. Be aware that any cloudiness in the water will skew the result higher. You also have high calcium hardness, and this also merits draining some water and replacing it if your fill water has a reasonable CH level.

    With a cartridge filter, normal water replacement slows down since you don't backwash.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    Join Date
    Apr 2008
    Central Texas
    Pete, I had to do the same thing to my pool last spring. I made up a manifold to fit a shallow well jet pump that I keep in the garage, which let me connect garden hoses to the pump and spread the pool water onto my lawn.

    I borrowed enough hoses at fill time to run hoses from 5 different spigots on my house and was able to fill my 26K gallon pool in right at 24 hours. 8)

    The good news is that it was FAR easier to keep my water clear afterwards.
    26,000 Gallon Gunnite IGP
    2 HP Challenger High Head Pump
    60sf Nautilus DE filter
    Polaris 280

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    frustratedpoolmom's Avatar
    Join Date
    May 2007
    SWSuburban Chicago, IL
    Drain and replace. If the CYA is really 400 it will probably mean 3 or 4 partial drains/fills before you get it to a manageable number. Drain 1/3, fill....test. Add chlorine if your fill water is not chlorinated. Repeat. Test again....My CYA is the same as it was at the end of last summer, after 2 partial drains/refills. It did not go down much at all, it's about 60-70 but I'm dealing with it....
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner

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