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Thread: Ph rising and alkalinity dropping

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    lmnconn's Avatar
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    May 2014
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    Ph rising and alkalinity dropping

    Last year our pool was new and we used trichlor pucks. We had no troubles with the pool and was very easy to maintain, however; after just one 3 month season, the CYA went up to around 90. We drained several inches and refilled several times toward the end of the season. Then drained below skimmers and returns for the winter. After filling back up for this season, CYA is high 30's to 40. We've been using BBB method this year to avoid the rise in CYA, but are now having terrible time with Ph constantly rising. I'm having to add Ph- every other day. I have dropped alkalinity to 60, but Ph still rises. I'm beginning to think it would be less maintenance and cheaper to go back to trichlor and just drain and refill to maintain CYA. We are on a well, so we do not pay for water. Any body else have any thoughts on this?
    St. Louis, MO, 25000 gal, 16x32 lagoon, vinyl, sand filter, Hayward pump, chlorine, install complete 9/12, Taylor TF100 test kit

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    Re: Ph rising and alkalinity dropping

    Pucks have a trade off. They will keep your PH down so you'll use less muriatic acid as they're acidic, yet you end up with too much CYA.

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    JasonLion's Avatar
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    Re: Ph rising and alkalinity dropping

    There are a couple of possibilities. First, exactly what pool chemicals are you using? There might be something you are adding that is affecting the PH. Second, do you have any major sources of aeration? Things like fountains, waterfall, SWG, spa, etc. Third, it would help if you post a complete set of water test results, there might be some hint there. And fourth, what are your fill water PH and TA levels? And have you been topping off the pool frequently, or has that not been needed?
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    lmnconn's Avatar
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    Missouri
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    Re: Ph rising and alkalinity dropping

    Have been using 8.5% bleach and HTH brand Ph- No other chemicals have been needed

    FC 3.8
    CC. 0
    Ph 8 (but constantly lower it to 7.4 and it creeps up in 3 days)
    Alk. 60
    CYA 40
    CH 200

    Our untreated well water tests:
    Ph7.2
    Alk. 250
    CH 200

    We've had quite a bit of rain, so have only had to top off one time since opening pool in March. No aeration to cause rising Ph.
    St. Louis, MO, 25000 gal, 16x32 lagoon, vinyl, sand filter, Hayward pump, chlorine, install complete 9/12, Taylor TF100 test kit

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    JasonLion's Avatar
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    Re: Ph rising and alkalinity dropping

    That is difficult to explain then. When you do top off the pool the TA will go up noticeably and I would expect the PH to go up at that point. But if you haven't been topping off the pool I can't explain it.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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