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Thread: General pH question

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    Join Date
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    General pH question

    I am currently doing the shock process on the pool due to cloudy water after a heavy storm, following strictly the "how to shock" instructions. Started yesterday, had a pH of 7.5. All summer I have had no problems with the pH. Today all of a sudden the pH is reading 8.2+. Could adding all the bleach during the shock process increase the pH? Will follow the pool calculator and add muriatic acid today.

    Second question is how important is the CH? It is testing only at 50. concrete bottom pool. Can I add this during the shock process or should I wait? could the low CH affect the clarity of the pool water?

    FC 28 checking every 2 hrs
    CC 0
    TA 80 (was 60 2 days ago)
    CYA 40 (keep trying to raise this every week, won't seem to budge)
    CH 50
    salt 3600

    test kit tf 100, 40x20 approx 24,000 gal. sand filter.
    30k gal, IG plaster epoxy paint and stainless steel sides, built ~1980, sand filter, TF-100, SWG Circupool RJ-45, Dolphin M400.

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    Mod Squad Bama Rambler's Avatar
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    Re: General pH question

    It does increase the pH a little but more importantly high FC affects the pH test. It makes it read falsely high. Don't worry about the pH until you finish shocking.

    Good on you for following the shock process carefully.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: General pH question

    thanks so much. will hold off on adjusting pH until shocking is done. I am learning!!

    any advice on the calcium?
    30k gal, IG plaster epoxy paint and stainless steel sides, built ~1980, sand filter, TF-100, SWG Circupool RJ-45, Dolphin M400.

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    Mod Squad Bama Rambler's Avatar
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    Re: General pH question

    You need to add some but I'd wait till you're done shocking.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    CUTiger78's Avatar
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    Re: General pH question

    Quote Originally Posted by docxo
    any advice on the calcium?
    Yeah, calcium is important, too, for a gunite/plaster pool. From my experience, low CH in an old plaster pool can contribute to lack of clarity. YMMV.

    From Pool School:

    CH - Calcium Hardness

    Calcium hardness indicates the amount of calcium in the water. Over time, water with low calcium levels will tend to dissolve calcium out of plaster, pebble, tile, stone, concrete, and to some extent fiberglass surfaces. You can prevent this from happening by keeping the water saturated with calcium. In a vinyl lined pool there is no need for calcium, though high levels can still cause problems. A plaster pool should have CH levels between 250 and 350 if possible. Calcium helps fiberglass pools resist staining and cobalt spotting. If you have a spa you might want to keep CH at at least 100 to 150 to reduce foaming. CH contributes to the CSI which indicates the tendency for plaster damage or calcium scaling.

    You increase CH with calcium chloride, sold as a deicer and by pool stores, or calcium chloride dihydrate, sold by pools stores for increasing calcium. You lower calcium by replacing water or using a reverse osmosis water treatment.
    36K gallon 42X22 gunite/plaster kidney-shaped IG;
    1 hp Hayward Super Pump (new in 2012);
    Hayward S244T sand filter w/ Zeosand (both new in 2009);
    175K BTU LAARS Lite2 LG natural gas heater; Polaris 380;
    TF-100 test kit.

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