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Thread: Question on pH stabilizing

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    Join Date
    Aug 2012
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    Near Sacramento, CA
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    Question on pH stabilizing

    Hello. Thanks to everyone that participates in this forum!!

    Recent test results:

    FC 4
    CC 0
    pH 8.1
    TA 100
    CH 300
    CYA 40

    I use liquid chlorine (10%) & MA (31.45%).
    The water in my town is very alkaline - so after refilling it in the summer due to the water being old (high CYA, CH, etc.) and learning about water balance here - I slowly worked my TA down to 100. I was hoping my pH would stabilize around 7.8, but instead it seems to always go to 8.1 - so then I add a little acid, the TA goes down a little (but pretty slowly seems like).

    Am I destined to just have to continue to add acid to reduce the pH and eventually start to add baking soda to raise the TA?
    Is it OK if my pool is stabilizing at pH of 8.1 - then I can just choose to lower it for swimming (all the while trying to keep my TA at around 80)??

    Thanks in advance.
    Outdoor IG Plaster Pool @18,000 gallons
    Cartridge Filter: Jandy CL580 (filter area 580 ft2, Max Flow 150 gpm, 6-hr capacity 54,000g)
    Pool Built est. 2002

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    duraleigh's Avatar
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    Re: Question on pH stabilizing

    Is it OK if my pool is stabilizing at pH of 8.1
    Not really. Keep your pH in the 7's........that's the advice suggested in Pool School.

    Maintaining your pool water within Pool School's guidelines will give you the results you want. However much acid it takes to keep your pH in the 7's is just part of the cost of doing business......much like adding chlorine, CYA or any of the other things necessary.

    Make pH your primary target (aside from chlorine ) and let the TA fall where it likes as long as it stays within reason.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Richard320's Avatar
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    San Dimas, CA (LA County)
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    Re: Question on pH stabilizing

    Quote Originally Posted by yeomanflood
    The water in my town is very alkaline - so after refilling it in the summer due to the water being old (high CYA, CH, etc.) and learning about water balance here - I slowly worked my TA down to 100. I was hoping my pH would stabilize around 7.8, but instead it seems to always go to 8.1 - so then I add a little acid, the TA goes down a little (but pretty slowly seems like).

    Am I destined to just have to continue to add acid to reduce the pH and eventually start to add baking soda to raise the TA?
    Is it OK if my pool is stabilizing at pH of 8.1 - then I can just choose to lower it for swimming (all the while trying to keep my TA at around 80)??

    Thanks in advance.
    What you're describing is perfectly normal. If you plug your numbers into pool calculator then go way down to the bottom where it says "Effects of Adding Chemicals" you'll see that adding, say, 28 oz of acid will lower pH by .37 but TA will only drop 6.1 ppm. So pH is affected more than TA. pH will climb again, and you keep repeating it. But you'll notice as the TA goes down lower and lower that the speed at which the pH rises slows down. And that the amount of acid to keep pH stable goes down too. Eventually you'll hit the sweet spot - and you're getting close, now - where the acid demand will drop to only needing a cup or so once or twice a week.

    I doubt you'll ever need to add baking soda. Just refilling the splashout and evaporation with the alkaline tap water will keep it up.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Join Date
    Aug 2012
    Location
    Near Sacramento, CA
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    Re: Question on pH stabilizing

    Thanks, guys. I will follow your advice and do that and let you know how it goes!
    Outdoor IG Plaster Pool @18,000 gallons
    Cartridge Filter: Jandy CL580 (filter area 580 ft2, Max Flow 150 gpm, 6-hr capacity 54,000g)
    Pool Built est. 2002

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    UnderWaterVanya's Avatar
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    Re: Question on pH stabilizing

    My pH rose until my TA reached about 70-75.

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    Inlaws Pool Boy since June 14th 2012, Pool built ~ 2003, In-Ground, 16'x32'
    13500 gal, Vinyl Liner, Fiberglass Slide, TF-100 Test Kit, Hayward 210T
    sand filter, A.O. Smith 1.5HP main pump motor (C48L2N134C1),
    Hayward SuperPump (model ?), Polaris 380 & PB4 Booster Pump

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    Join Date
    Aug 2012
    Location
    Near Sacramento, CA
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    Re: Question on pH stabilizing

    Thanks for sharing.
    Outdoor IG Plaster Pool @18,000 gallons
    Cartridge Filter: Jandy CL580 (filter area 580 ft2, Max Flow 150 gpm, 6-hr capacity 54,000g)
    Pool Built est. 2002

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