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Thread: calcium hardness decreasing

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    TrevNJPool's Avatar
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    calcium hardness decreasing

    Just a question for my understanding. My CH has been decreasing since my first test results in early July. My original tests were 150. I added some to bring it up to closer to 200. It remained there for a few days then started decreasing. It is now down to 100. What causes the decrease? I know it doesnt really matter because i have a vinyle liner but would still like to keep it around 200. My newest test reults are:
    FC 10
    PH 7.1ish
    CC 0
    CH 100
    TA 90
    CYA 35

    I havent added anything except for Borax for ph, bleach, cal-hypo
    40x18 Lazy L Rectangle
    29500gal IG w/ vinyl liner
    HAYWARD S244T 300lb sand filter
    Hayward Super Pump 1 1/2hp

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    Re: calcium hardness decreasing

    Would have to be a leak, or from you doing some major backflushing.
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    Re: calcium hardness decreasing

    I wish my CH would go down on its own.
    chiefwej
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

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    TrevNJPool's Avatar
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    Re: calcium hardness decreasing

    I have had to blow water out 2 times for a lot of rain and add some due to evaporation but no huge amounts of water. I thought that was one of those things that stayed in the water
    40x18 Lazy L Rectangle
    29500gal IG w/ vinyl liner
    HAYWARD S244T 300lb sand filter
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    Mod Squad jblizzle's Avatar
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    Re: calcium hardness decreasing

    The CH does stay in the water. The only way it is lowered is if you are replacing the pool water with water that has a lower CH (like rain). I think the CH can also go down if you are getting a LOT of calcium scaling, usually from having high CH and pH, not likely the issue here.
    Jason, TFP Moderator
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    Re: calcium hardness decreasing

    Your FC is quite high for your current CYA level and your pH is a bit in the low side. Do you normally keep your pH and FC at those levels??



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    Re: calcium hardness decreasing

    What kind of test kit are you using?
    Exactly what kind of Calcium product are you using?
    18,000 Gallon Aboveground. Sand Filter with 2HP 2 speed Pump.

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    TrevNJPool's Avatar
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    Re: calcium hardness decreasing

    The FC is drifting down at the present moment due to slamming because i found some algae when i returned home from vacation. I usually keep FC at around 7ppm. Since my FC was high i didnt bother raising the PH yet. Plan on doing that 2mrow once i can check the PH again

    Using the TF100. Dont know what the CH product is. Put 25lbs in sometime in july. I keep records of my test results an noticed it was drifting down.
    40x18 Lazy L Rectangle
    29500gal IG w/ vinyl liner
    HAYWARD S244T 300lb sand filter
    Hayward Super Pump 1 1/2hp

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    Patrick_B's Avatar
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    Re: calcium hardness decreasing

    The product isn't the problem. You are simply lowering it by adding fill water with less CH. I wouldn't worry much with your type of pool.
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