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Thread: Constantly rising pH.

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    Join Date
    Feb 2013

    Constantly rising pH.

    Background: we bought the house in Feb 2013. In Jan 2013, just before we bought, the previous owner resurfaced the pool (plaster). As you can imagine during that time of year, the surface was not regularly brushed immediately afterwards (incredibly cold & windy)...not sure what impact that has.

    For the rest of 2013 and 2014, I watched pH rise over 7.8 if I didn't add muriatic acid every 2-3 days.
    After the heavy rains last month, CYA dropped from 50 to < 20. In prep for summer, I used tri-chlor pucks for a couple weeks to bring CYA back up to 35...that nicely kept pH down. Now that CYA is up to a reasonable level (leaving a bit of room for vacation this summer) I'm back to bleach...and pH maintenance: it is behaving the same as years past.

    Here are most recent test results:
    FC - 4.5 (maintain between 4 and 7 with 1 to 2 qts bleach/day)
    CC - 0
    pH - 7.8
    TA - 50
    CH - 225
    CYA - 35

    Water is crystal clear.

    Question 1: Since baking soda is a buffer, would it help stabilize pH if I drive down pH to 7.2 then raise TA to 70 or 80?
    Question 2: IF the pool has a natural tendency toward pH 7.8+, would I be better off managing CSI or keep chasing pH?
    TF-100 w/ Speedstir :)
    ~9000 IG gunnite pool, attached 6-8 person spa. Features: spa spills to pool, waterfall feeds spa, and 3 fountains in a "river" feed pool.
    Jandy Stealth 1.5 main filter pump, Hayward 2.0 booster, Hayward Swimclear 4030, Hayward H350. Caretaker in-floor pool cleaner

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    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: Constantly rising pH.

    Many pools seem to seek a pH around 7.8, which is fine. I would first try to leave it alone, lowering it when it reaches 8.0 but only lowering it to around 7.5 or 7.6. You might be surprised at how long it stays in the 7's.

    I have never used CSI as a parameter so I can't help.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Columbia, SC

    Re: Constantly rising pH.

    Generally we don't agonize over CSI as long as you are keeping all your parameters within our recommendations. You can see them on this page. Pool School - Recommended Levels

    I have a sheer decent which adds a lot of aeration to my pool. Thus my pH tends to rise and I bring it down with acid. When the TA gets around 50 I bring it back to 70-80 with baking soda.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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