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Thread: Causes for calcium leaving water?

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    Causes for calcium leaving water?

    I tested my source water that I use to (re)fill the hot tub for ch. It tests 170. On more than one occasion, about 5 to 6 weeks after refilling the hot tub the ch tests so low that I can't test for it.
    I didn't know that calcium could be lowered in the water without draining and refilling with water that had less. Where does my calcium go?

    With new water in the tub I have virtually no foam but by the time the ch tests so low I have a moderate amount of foam.

    22,000 rectangle pool with custom inpool steps sand filter and new autopilot swg

  2. Back To Top    #2

    Join Date
    May 2007
    South Central NJ

    Re: Causes for calcium leaving water?

    Is the water still warm or hot when testing?

    Are you using strips to test for calcium?

    What are the other chem readings and how are you testing?

    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  3. Back To Top    #3

    Join Date
    Mar 2007
    San Rafael, CA USA

    Re: Causes for calcium leaving water?

    That is very odd. By any chance are you using a phosphate buffer for pH control? These are sometimes found in "one product does everything" miracles, that aren't. Phosphates will precipitate calcium out of the water.
    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
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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