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Thread: Calcium hardness

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    H-12 1/2 Mike's Avatar
    Join Date
    Apr 2014
    Highland Village, TX

    Calcium hardness

    What causes the calcium hardness levels to deplete as the water temperature goes down?
    Chlorine = 8.0
    Ph = 7.6
    Total Alkalinity = 140
    Calcium hardness = 190 (last week it was 210 and I added 4 lbs of calcium chloride).
    CYA = 50
    Temperature = 51 (pool - last week it was 61)
    Pool is 16,400 gals. Gunite.
    16,400 gallon
    Cartridge Filter
    Intelli-Flo @ 2000rpm

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    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: Calcium hardness

    I am not aware that temp has any affect on on CH.

    I will mention that the difference of 20 ppm is not very significant on CH.

    The current instructions in the TF-100 suggest a 10 ml pool sample giving each drop of R-0012 a value of 25 ppm instead of 10 ppm value you used. 25 ppm accuracy is just fine for our purposes.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3

    Join Date
    Jul 2012
    Central Texas

    Re: Calcium hardness

    Has your portion of Texas experienced significant rain? That could account for some depletion. Mine has dropped 40 ppm over the last 2 weeks from rain and flow out.
    Central TX / 12K GAL / IG / SWG / DE filter / Pentair SVRS & 3 swim jet pumps / Spa bench and jets / Single body of water / No heater.

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