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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

  2. Back To Top    #2

    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. - Forum owner
    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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