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Thread: rising pH

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    rising pH

    I have a 25,000G above ground pool. What would cause the pH to keep climing? My recent readings last night are:

    pH 7.8 (was 7.4 2days ago) No water added, no rain. Shocked with Ca++ hypochlorite once the night before this reading.
    TA 100
    CYA 60
    FC 6
    Hardness 260

    I use 10% liquid chlorine. Don't use algecide. Water was crystal clear but has just a very little bit of cloudiness now...shocking didn't help. Is the pH causing this? Why would the pH clime?


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    Mod Squad woodyp's Avatar
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    Apr 2010
    East Texas

    Re: rising pH

    Are you using any kind of water feature or aerator to cool the pool water down? That'll do it!
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    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: rising pH

    The cloudiness may have been because of using Cal Hypo as your method of shocking. You have enough calcium in the pool already and I would stop using it. Simply use the 10% LQ for's do the same job and probably eliminate that cloudiness. That said, the cloudiness will likely clear up on it's own very soon.

    Most (but not all) pools tend to rise in pH. Some a little slower or faster than others. Bring your pH down to around 7.2 with muriatic acid and see how long it takes it to get bacl to 7.8
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: rising pH

    Thanks! It was cloudy prior to using the Ca++ shock...but I'm sure that didn't help any. I added the acid and within 6hrs the cloudiness was gone. pH is back down to approx 7.3 (if i'm reading the color test right). This is only my 2nd year with the pool...last year was a disater...the pool company had me so messed up with their readings and instructions. Thanks goodness I found this site over the winter! I threw all the **** they had me buy last year in the trash (except for a few left over bags of Ca++Hypo shock), have been testing the water myself, and have used nothing but 10% liquid chlorine and some acid this year...what a difference!! THANKS for the help!!!!!


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    Re: rising pH

    Most (but not all) pools tend to rise in pH. Some a little slower or faster than others. Bring your pH down to around 7.2 with muriatic acid and see how long it takes it to get bacl to 7.8[/quote]

    I got my ph down to around 7.3. Now about 4days later my ph is back up to 7.8 and the pool is clouding up again.
    ph 7.8, FC 6, TA 90, temp 80deg. I haven't done anything to it since getting my ph down to 7.3 except add cholorine 10%. Any thoughts on why the ph is going up so fast????


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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: rising pH

    The two most common causes of rising PH are fresh plaster (obvious doesn't apply) and relatively high TA combined with aeration (SWG, waterfall, fountain, rain, kids splashing, etc).

    There can also be temporary PH swings when you change the FC level significantly.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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