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Thread: Rising PH

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    Rising PH

    My PH has been rising for the past six months and I can't determine why. Get's up to 8.2 and I add acid and goes to 7.7 For the past 3 years has held steady at 7.8

    test results have been as follows:

    fc: 10
    cc: 0
    ta 100
    ch 320
    cya 70

    ph 7.7 - 8.2

    any help appreciated. TJ
    28,000 gallon IG pool, plaster, built approx. 1970.
    1 1/2 " plumbing. Pentair, Intelliflo 3 hp variable speed.
    Crystal Water cartridge filter system, model #425
    Dolphin Deluxe 4,

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    Re: Rising PH

    Have you tried lowering your TA?

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    Re: Rising PH

    Thats not surprise since your TA is on the high side. Consider your TA as a pH buffer, the higher it is, the more tendency your pH will have to want to rise higher and faster. Lowering your TA to 60 should drastically reduce the speed of the pH rise and could ultimately hold the it at bay since a pH of 7.8 and a TA of 60 is nearing being at equilibrium with the carbon dioxide content in the atmosphere (carbon dioxide outgassing being the primary driver of pH rise).

    Any form of aeration also contributes to pH rise so limiting that and lower TA values would be in your best benefit.
    -Brian-
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    Mod Squad pooldv's Avatar
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    Re: Rising PH

    +1 to all of the above.
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    Re: Rising PH

    100 TA will be the primary reason.
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    Re: Rising PH

    It's odd that it was steady for three years and suddenly there's unexpected ph rise. Did anything change recently? Maybe a replaster or add salt system?

    What are you doing for chlorine?

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    Re: Rising PH

    8.25 Bleach.
    I bought a tf-100 test kit late last year. All of my test results were good except cya -125 and ta -70. I thought it should be been 80 and 120. I targeted 100, in the middle. Also the pool store was performing test for previous 3 years and also reported TA @ 100. OH Boy. I should lower to around 70 and the ph should behave. thanks to all.
    28,000 gallon IG pool, plaster, built approx. 1970.
    1 1/2 " plumbing. Pentair, Intelliflo 3 hp variable speed.
    Crystal Water cartridge filter system, model #425
    Dolphin Deluxe 4,

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    Re: Rising PH

    That is exactly what happened then. The recommended TA value of 80-120 is not correct. There is no reason to raise the TA unless it falls below 50-60, the pH falls (very uncommon in most cases) or becomes erratic.
    -Brian-
    33K Pool/Spa, Pentair Equipment
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    Davis Custom Construction - Home Page

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    PH ?

    My PH keeps rising because my TA is ~ 100. I installed my home made aerator yesterday. Should raise my PH without raising TA Lowered PH to 7.0 So far my PH has not moved higher from 7.0 I wait for PH to rise to 7.5 then lower again until my TA is ~ 70. My question is when I stop using the aerator what will happen? I stop when PH is 7.5 and TA IS ~ 70. I think the TA will not go higher and same goes with my PH. (7.5) I'm concerned when I stop using aerator my TA will rise. Hopefully I am making sense to the forum. TJ
    28,000 gallon IG pool, plaster, built approx. 1970.
    1 1/2 " plumbing. Pentair, Intelliflo 3 hp variable speed.
    Crystal Water cartridge filter system, model #425
    Dolphin Deluxe 4,

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    Texas Splash's Avatar
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    Re: PH ?

    Every pool is different, but eventually they should both settle and find a "happy place" for your pool to where you won't have to do as much to maintain. For some folks, pH levels-off in the mid-7s with a TA at 70, other take TA down to 50-60 or so before pH stabilizes. It's a bit of a cat & mouse game for a while.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    Re: Rising PH

    Please do not post different threads for your subject. Even if they're a bit different keep them together. I have merged your latest post
    Dave S.
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    Re: PH ?

    Quote Originally Posted by TJTJ View Post
    My PH keeps rising because my TA is ~ 100. I installed my home made aerator yesterday. Should raise my PH without raising TA Lowered PH to 7.0 So far my PH has not moved higher from 7.0 I wait for PH to rise to 7.5 then lower again until my TA is ~ 70. My question is when I stop using the aerator what will happen? I stop when PH is 7.5 and TA IS ~ 70. I think the TA will not go higher and same goes with my PH. (7.5) I'm concerned when I stop using aerator my TA will rise. Hopefully I am making sense to the forum. TJ
    The purpose of aerating is to get the pH to rise quickly when you are aggressively trying to lower the TA. If speed is not a concern, drop the pH to 7 and add acid when it reaches 7.4 (no aeration) to lower it back down to 7. This will no doubt be a slow process but if you aren't in a hurry, why rush?
    -Brian-
    33K Pool/Spa, Pentair Equipment
    POOL BUILD
    Davis Custom Construction - Home Page

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    Re: Rising PH

    Your TA will not rise due to lack of aeration. Only your pH rises as a result of aeration. Acid lowers both pH and TA.

    TA only increases when you add a source of alkalinity such as baking soda (sodium bicarbonate) or soda ash (sodium carbonate). Also, your fill water will add TA depending on the source. You can easily measure the TA of your fill water to see if it is a significant source of alkalinity.


    Matt
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    Re: Rising PH

    014.jpg

    I have been testing my PH twice a day, always reads the same ~ 6.9 to 7.0
    I always drop 5 of the PH regents. TA is always ~90 PH just doesn't want to go higher for some reason. Can't figure out...
    I made my aerator and inserted into my return, where the air is pushed out into the pool. Is this also the jet? Did I insert the aerator in the proper place? thanks, TJ
    28,000 gallon IG pool, plaster, built approx. 1970.
    1 1/2 " plumbing. Pentair, Intelliflo 3 hp variable speed.
    Crystal Water cartridge filter system, model #425
    Dolphin Deluxe 4,

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    Texas Splash's Avatar
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    Re: Rising PH

    Maybe that's just not enough aeration for that size pool. From the pic, it doesn't appear to really stir things up very much to raise your pH. Here's a couple more examples:
    Smoking hot pool water
    Best Method to Aerate

    On a side note ... your water looks great.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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