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Thread: CH in the DFW area

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    Join Date
    Feb 2008
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    Flower Mound, TX
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    CH in the DFW area

    I have been in this house for almost a year now and likewise, I have been caring for my pool over the same time span. One of the tests that has always perplexed me about my water chemistry was been the calcium hardness test. I had issues with fading endpoints at first but I was able to get that resolved and now I trust the accuracy of the result wholeheartedly.

    I have always had high CH reads - anywhere from 425 to 600. I just resulted at 600 ppm. The reason that this confuses me so is because I run BBB. I have an in-ground gunite pool and no SWG. Just straight up BBB. I have never used cal-hypo and I have never had to shock, not ever. This pool is almost 7 years old so there are no plaster curing issues to be concerned with. The only thing that I can think of that would be causing a high CH would be the possibility of the previous owner shocking with cal-hypo routinely. The fact that I have a cartridge filter and therefore, no backwashing or waste settings limits my water elimination to splash out and storm water overflow down the check drain on the tile. To put it this way, my CYA barely moves. I have dropped a total of 5 ppm of CYA over the course of the year. Knowing that calcium and CYA both must be actively removed by draining water, there seems to be no other explanation.

    Our municipal water calcium hardness by the way, runs anywhere from 150 to 200 ppm here depending on the time of year.

    I don't really have any scaling issues. Should I just leave it alone or should I go ahead and do a partial drain and refill? For what it's worth, my CSI is and has always been within normal limits.

    Thanks!

    Craig
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

  2. Back To Top    #2
    JasonLion's Avatar
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    May 2007
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    Silver Spring, MD
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    Re: CH in the DFW area

    It is probably from evaporation. When water evaporates the CH is left in the pool. When you add water to bring the water level back up more CH comes in with the fill water. Over time the CH level increases. This is especially true if you have a cartridge filter. Backwashing, or any other form of water removal and replacement, lowers the CH level.
    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

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    Re: CH in the DFW area

    That makes as much sense as anything I suppose. With small additions of tap water over a period of time and very little rain to cause overflow, I see the reason for the rise. I think that I am going to go ahead and do some partial drains and refill. Scaling, to my knowledge, has not yet occurred but if my CH continues to rise unchecked, then it is simply a matter of time.

    Thanks Jason.
    10K gallon IG gunite with waterfall; Pentair CC320P filter; WhisperFlo 2 HP pump
    TF Test Kits - Pool Math - Pool School
    "It depends."- JohnT

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    revstriker's Avatar
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    Apr 2008
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    Re: CH in the DFW area

    Jason, I'm in McKinney and have not had an issue with CH. Currently running around 240.
    10K White Plaster Pool Built in 2007. Hayward Pump and DE Filter, Hayward Navigator, Liquidator (Removed due to issues), Solar Blanket, BBB user.

  5. Back To Top    #5

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    Tucson area, AZ
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    Re: CH in the DFW area

    Quote Originally Posted by revstriker
    Jason, I'm in McKinney and have not had an issue with CH. Currently running around 240.
    You also have a DE filter, and, therefore, have to backwash; Jason has a cartridge, and, therefore, does not. Makes a difference as to how much pool water is replaced on a regular basis.
    Above ground soft side Omega pool
    20 feet diameter, 4 feet deep
    Hayward sand filter
    Hayward 1 HP Matrix pump
    Hayward Aquabug Automatic Pool Cleaner

  6. Back To Top    #6
    revstriker's Avatar
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    Re: CH in the DFW area

    Quote Originally Posted by Swimgirl
    Quote Originally Posted by revstriker
    Jason, I'm in McKinney and have not had an issue with CH. Currently running around 240.
    You also have a DE filter, and, therefore, have to backwash; Jason has a cartridge, and, therefore, does not. Makes a difference as to how much pool water is replaced on a regular basis.
    True. But I don't backwash that often. I've only backwashed once this year.
    10K White Plaster Pool Built in 2007. Hayward Pump and DE Filter, Hayward Navigator, Liquidator (Removed due to issues), Solar Blanket, BBB user.

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