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Thread: First Tests - Order of ajustments?

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    bdenehy's Avatar
    Join Date
    Mar 2008
    Putnam Co., NY

    First Tests - Order of ajustments?

    I opened up yesterday to a "dirtier" pool than usual. I took the cover off last week but the pump motor needed to be replaced. After bleaching, vacuuming, a night of filtering, and 3 backwashes, the water looks okay, just a little cloudy in the deep end. Here are my numbers from last night:

    FC 10.5
    TC 10.5
    PH 8.4
    TA 40
    CH 100
    CYA ~30

    This morning FC was 8.0 and PH was 8.3. So, two questions:
    1) is the 2ppm drop in FC overnight a reason to shock? I don't usually need to shock upon opening, but it was a pretty warm winter here and I did leave it stagnant for 4 days or so uncovered.
    2) I want to lower PH to around 7.5 and raise TA to ~100. Should I treat the PH with acid before messing with TA? If so, how far below my 7.5 target should I shoot for, since baking soda will bring them both up at the same time?

    Thanks very much,
    35,000 gal vinyl, Hayward DE Filter, Hayward 400k BTU heater, SWG, Polaris 380 w/booster pump, plenty of dog hair in the skimmers.

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    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: First Tests - Order of ajustments?


    In your case, get the pH and TA right first. That is usually NOT the case but yours needs some adjustments.

    1. bring your TA up around 100 using baking soda. It will NOT affect pH very much.

    2. Now bring your pH down to 7.5. Use muriatic acid. Your TA will come down, too.

    3. Now retest your pH and TA and adjust if necessary.

    Then, you can deal with your FC and CYA
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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