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Thread: PH constantly dropping??

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    PH constantly dropping??

    We have had a spell of really mild weather and during that time there wasn't much swimming taking place. Chlorine levels have been fine but I've having a really hard time maintaining what I consider a good PH level. I've been struggling to maintain a PH level above 7.4 for more than a couple days before I have to add Borax, I've gone through more Borax in the past week than I did all summer. Every few days the PH drops to the 7.0-7.2 range, I then add Borax according to PC to bring the PH up to 7.8. I check either later that night or the next morning and I'm not getting anywhere near the 7.8 I'm wanting, it's closer to 7.5-7.6. I've checked my TA repeatedly and it is running around 100.

    The pool had been covered with a solar cover
    Temps over the past few weeks have averaged a high of 75-80.
    Filter/pump runs 24/7

    Any ideas?? I've read that PH regulates itself by being exposed to air, sun, and swimming so I'm hoping it's just a case of my kids need to swim more.

    Thanks in advance
    24 Ft Sharkline Matrix , ~15,200 Gallons
    Pentair SD60 w/ 2 speed 1.5 HP Dynamo pump
    Taylor K-2006 --- BBB

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    Join Date
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    Re: PH constantly dropping??

    Same thing happens when I have my cover on. When I take it off the pH returns to normal 7.7. I just accept it and don't try to fight it. CO2 outgassing/exchange seems to be the cause (the cover prevents it).
    18x36 inground vinyl lined, Hayward sand filter and tablet chrolinator, approx 18k gallon

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    Re: PH constantly dropping??

    Any ideas??
    The most common cause of pH drop by far is the use of tri-chlor pucks.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: PH constantly dropping??

    My situation is similar: stable around 7.6 (TA ~110-120), now with the cover on most of the time it's stuck around 7.4.

    My TA was down around 80 when I got all the way down to 7.2 (tested when I started using the cover daily). I need to test my TA again, should be around 90-100. pH was 7.4 last night, but I would rather 7.6 of course.

    Most likely I will also be building a new attachment that aerates more effectively.
    Aaron
    [ Vogue Vectra 24' AG | Hard plumb: Hayward Power-Flo Matrix 1HP 2-speed, 27" sand filter & Pentair MiniMax 100 NG | Taylor K-2006 | Central IL ]
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    Re: PH constantly dropping??

    Quote Originally Posted by duraleigh
    Any ideas??
    The most common cause of pH drop by far is the use of tri-chlor pucks.
    not a single one has been in the pool

    Thanks for the replies, who would have guessed we would have a heat wave from April-July and then fall temps in August
    24 Ft Sharkline Matrix , ~15,200 Gallons
    Pentair SD60 w/ 2 speed 1.5 HP Dynamo pump
    Taylor K-2006 --- BBB

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    Re: PH constantly dropping??

    not a single one has been in the pool
    How do you chlorinate?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: PH constantly dropping??

    Quote Originally Posted by duraleigh
    not a single one has been in the pool
    How do you chlorinate?

    I've used BBB from day one.

    By the way thanks for the quick turnaround on the test kit supplies
    24 Ft Sharkline Matrix , ~15,200 Gallons
    Pentair SD60 w/ 2 speed 1.5 HP Dynamo pump
    Taylor K-2006 --- BBB

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    Re: PH constantly dropping??

    I've used BBB from day one.
    By the way thanks for the quick turnaround on the test kit supplies
    You're welcome! Thanks for your business.

    So, you don't use pucks. Hmmm.

    I am not aware that covering your pool would drop the pH. It makes sense that it would stabilize it some but not lower it.

    There must be something we're overlooking.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: PH constantly dropping??

    I agree. With a cover on the pool and no carbon dioxide outgassing, the pH would be stable unless something acidic was getting into the pool. That assumes that the FC level is constant. A dropping FC level will lower the pH, but not that noticeable unless going from rather high levels to lower ones. Acidic chemicals include acid (of course), Trichlor, Dichlor, bromine tabs and non-chlorine shock (MPS). The tannins from leaves can be acidic, but with a cover I don't see how they would get into the pool. New pool plaster can have the pH rise, but I don't see how it would drop unless the water was over-saturated with calcium carbonate and there was scaling.
    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
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: PH constantly dropping??

    Just happened to me again today. Opened the pool up and PH was right between 7.2 and 7.4. By the time I covered it tonight it was back up to 7.6. My last PH test prior to this morning was Tuesday evening and it was 7.6. I've always chalked it up to my TA being low enough to buffer outgassing that occurs with our "normal" pool usage, but once covered it's just low enough to stabilize PH at 7.2. I'll be the 1st to admit not knowing the science behind it, and it does not bother me the least bit since 7.2-7.4 feels much more comfortable to my eyes, but I know I'm not imagining this.

    Frustratedpoolmom used to experience the same a few seasons ago when I originally asked about this on the forum.
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

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