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Thread: High Calcium with TF Test Kit

  1. Back To Top    #1

    Join Date
    May 2007
    Rocklin, Ca

    High Calcium with TF Test Kit

    Hi All,

    I just received my TF Test Kit and my first test revealed a troubling result. First my pool has only had water in it for about 45 days.

    Up until now I have been using a HTH 6 Way test kit and at first had good test numbers. As I had posted in another post, I started having trouble with my hardness test. After adding the indicator drops the water turned yellow. If I titrated it out anyway I got the same result (CH=280) as when the color was normal. I didn't worry too much about this situation because I knew mew new test kit was coming.

    My first set of numbers using the TF Test Kit

    FC 6.5
    pH 7.4
    TA 160 (I have been running my waterfall a lot to try and decrease this)
    CH 470
    CYA 45 (I am slowly increasing this up to 75)
    Temp 79

    My TA had been slowly trending down from 120 down to 100 with the HTH. I didn't using both test kits on the same day.

    My tap water has a CH of 30. I have heard of calcuim leeching out of the plaster. Should I be concerned about my CH level? Will it slowly decrease as water gets splashed out and the auto fill fills it back up. Should I do a partial water change?


    11000 Gals, Intelliflo, Sta-Rite Cartridge, Polaris 360

    Pool I built in my old house: my-new-pool-build-t4534.html

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: High Calcium with TF Test Kit

    While your CH level is a little high, it isn't a serious problem right away. Just keep your PH below 7.6 until you can get the TA level down to a more reasonable number and you will be fine.

    Fresh plaster will increase the PH, TA, and CH levels in the water fairly rapidly for the first three or four weeks. Presumably that is how your CH got so high.

    There is also a possibility that there has been some kind of testing error. If the TF-100 numbers remain the same the next time you test then I would believe the TF-100 numbers over the HTH numbers.
    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

  3. Back To Top    #3

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: High Calcium with TF Test Kit


    It's never a bad idea to back up the TF-100 test with a second result (like from a pool store you trust) but, generally speaking, the CH test has been pretty reliable based on feedback here on the forum.

    As Jason said, you're okay as long as you keep your pH down.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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