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Thread: pH constantly high

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    Daf-Tekno's Avatar
    Join Date
    Sep 2014
    Calgary / AB

    pH constantly high


    I've just started up my hot tub after having fitted a ChlorMaker salt chlorine generator.

    I've got my Salt to 2,000, CH to 300 and TA to 75, but my pH keeps going over 8.
    And if I add muriatic acid to lower it, it'll lower the TA too!

    I know that adding the borates will help stabilise the pH, but I read that you shouldn't add the Borax / Muriatic acid until the pH & TA are at the correct levels, so I can't add them yet.

    Is the chlorine from the SWG raising my pH on a constant basis..?
    If so, how do I work around this?

    My pH was under 7, so I ran the tub for 40 mins with all air jets & waterfall on.
    Then it read over 8!
    Jacuzzi J480 (2008) 1700 litres, Balboa ozonator, Delta EZ-18-120 UV lamp via custom 6-way 2-tier timer solenoid array, 2 x Waterway 4HP main pumps,
    1 x Aqua-Flow 1/15 HP circ pump, ChlorMaker IL SWG, SmartSeal + Roxul skirting insulation, 8' x 8' ThermoFloat Spa blanket, 100" x 100" Gator coverall

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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: pH constantly high

    In a spa/hot tub the rules are different than in a pool. You seem to be mixing pool recommendations into what you mentioned reading above.

    With a spa/hot tub you simply lower TA until the PH stabilizes at something reasonable. There is no reason to aim for a TA of 75.
    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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    Mod Squad JVTrain's Avatar
    Join Date
    Feb 2014
    Central Minnesota

    Re: pH constantly high

    Due to the high amount of aeration in hot tubs, a lower TA will help combat pH rise. I lowered the TA in my spa to 50 and kept it there most of season. Just before my last water change, it was near 50.

    You can read the How do I use Chlorine in my Spa for reference on recommended levels. I know you're using a SWCG but the recommended levels are still valid.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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