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Thread: Odd pH raise

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    astronaut888's Avatar
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    Odd pH raise

    My pH tends to stay a bit on the "high" side of normal range.

    Typically hovers around 7.8 - possibly a BIT lower, as I'm not the best with reading the pink color gradation on the TF100 kit for some reason.

    I have been concerned about it sneaking higher than 7.8, so, I have attempted to lower it now 3 times.

    I have added 19oz (measured despite suggestions to NOT do so!!) on 3 separate occasions about 2 weeks apart.

    The pH responds by dropping to 7.5, possibly slightly lower, as would be expected.

    However, in a couple of days, it is reading 7.8 again

    It hasn't, to my knowledge, risen ABOVE 7.8 yet - I just find it strange that there is no "holding" of the pH change - is this typical?

    Also - I have a party coming up this weekend and the pool will get it's first true use with a large bather load - many kids, etc.

    I'm gonna kick the TC up a couple of ppm prior to swimmer arrival and check immediately once everyone leaves - but, was wondering what expected change in pH I should look for - should I lower the pH to 7.5 the night before or leave it at 7.8?

    Thanks in advance for entertaining the newbie questions
    20K gal, IG vinyl, 1 1/2 HP Hayward Super Pump , 100lb sand, installed 2000 - new liner/filter/pump March 2014
    TF-100 test kit

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    Smykowski's Avatar
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    Re: Odd pH raise

    Quote Originally Posted by astronaut888 View Post
    It hasn't, to my knowledge, risen ABOVE 7.8 yet - I just find it strange that there is no "holding" of the pH change - is this typical?
    Yes, this is normal. The lower the pH, the faster the rise. Most pools, when the chemistry is balanced, will find an equilibrium. Sounds like yours is around 7.8. The high bather load will create a lot of aeration, so I would probably drop the pH to 7.6 either the day before or morning of the party.

    Next week, let it ride, and see if/how long it takes to get above 7.8 - you may find that you can leave it at 7.8 for a long, long time before needing to add acid.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
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    Re: Odd pH raise

    I also struggle with high pH but I've been attempting to lower my TA. When I first opened a few months ago my TA was 120. I've gotten it down to 70 by lowering my ph to 7.2, aerating until it's 7.8 which only takes a few hours, then lowering it back to 7.2.

    It has worked because now my TA us at 70 my pH is still driving upwards but it's much slower now. I'm only adding acid every 3 days or so.
    17,000 inground gunite pool finished June 2013. Pentair variable speed something or another. Polaris cleaner, inline rainbow chlorinator. Using trichlor until CYA reaches 50-60.

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    astronaut888's Avatar
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    Re: Odd pH raise

    Quote Originally Posted by Dreampool13 View Post
    I also struggle with high pH but I've been attempting to lower my TA. When I first opened a few months ago my TA was 120. I've gotten it down to 70 by lowering my ph to 7.2, aerating until it's 7.8 which only takes a few hours, then lowering it back to 7.2.

    It has worked because now my TA us at 70 my pH is still driving upwards but it's much slower now. I'm only adding acid every 3 days or so.
    Should've said , TA is 100
    I have never had to address the TA but will look into lowering it thru aeration
    Not really sure what constitutes "aeration" actually, but will read up on the site
    Don't most folks use a fountain or some other method of breaking the water surface to do so?
    Would aiming the returns straight up aerate enough, I wouldn't think that would do much?
    20K gal, IG vinyl, 1 1/2 HP Hayward Super Pump , 100lb sand, installed 2000 - new liner/filter/pump March 2014
    TF-100 test kit

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    JasonLion's Avatar
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    Re: Odd pH raise

    Returns aimed up sometimes provide plenty of aeration, and are sometimes useless, it varies.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Odd pH raise

    Yes I am working on lowering my TA in an attempt to keep my ph from drifting. Now that I'm at a TA of 70, my ph stays at 7.5 a little longer before it creeps up. My target is to keep my ph at 7.2 because I have insane CH. It got up to 700 last summer, but now it's around 550 from all the rain we had this spring. A lower ph will keep my calcium suspended in liquid instead of scaling my tile or causing buildup in my pipes. I use the pool calc app to enter in all my numbers to check my CSI. Keeping my pH low is the easiest way to get my CSI in an acceptable range. I suppose I'm fine with a ph of 7.5 as shown here...

    17,000 inground gunite pool finished June 2013. Pentair variable speed something or another. Polaris cleaner, inline rainbow chlorinator. Using trichlor until CYA reaches 50-60.

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