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Thread: lowering PH with out lowing TA

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    lowering PH with out lowing TA

    I'm new to a pool ownership . Currently I am trying to lower PH without lowering TA.
    Currently my readings are:
    PH 7.8
    TA 70
    CYN 70
    FC 5
    CH 230
    TDS 1100

    When I add acid to the pool I end up lowering my TA to about 40-60 and my PH to 7.4. Then I add Sodium Bicarb to raise the TA to about 100 and up goes my PH. When I add sodium bicarb it raises my TA along with my PH. How can I maintain my PH at 7.2 -7.4 and my TA at 80 - 120 ?
    27x52 Round Opera Prestige (SunSports) AGP - w/hopper deep end (Wilbar insrt.)
    1.5 HP Sta-Rite pump w/21" Premium Sand Filter w/Main Drain installed - ~25,000 gal

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    JasonLion's Avatar
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    When you lower PH, TA will always go down. There isn't any way around that. But when you add baking soda TA should go up much more quickly than PH, so that when you add acid to bring the PH back down you should have gained some ground on TA.
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    Re: lowering PH with out lowing TA

    Quote Originally Posted by jlee1414
    I'm new to a pool ownership . Currently I am trying to lower PH without lowering TA.
    Currently my readings are:
    PH 7.8
    TA 70
    CYN 70
    FC 5
    CH 230
    TDS 1100

    When I add acid to the pool I end up lowering my TA to about 40-60 and my PH to 7.4. Then I add Sodium Bicarb to raise the TA to about 100 and up goes my PH. When I add sodium bicarb it raises my TA along with my PH. How can I maintain my PH at 7.2 -7.4 and my TA at 80 - 120 ?
    That's odd. Sodium bicarbonate should raise the TA by 30 points, while raising the pH by just .1. Are you sure you are using sodium bicarbonate, and not soda ash or something else?
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    Quote Originally Posted by JasonLion
    When you lower PH, TA will always go down. There isn't any way around that.
    For practical purposes, this is correct, but in commercial pools one can add carbon dioxide to the water to lower the pH with no change in TA. It's the exact opposite of outgassing. Over time, these pools do tend to rise in TA due to evaporation and replacement with fill water that contains some TA unless they have a lot of splash-out or backwash and fill water that is lower in TA than the pool.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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