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Thread: Alkalinity keeps rising

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    Alkalinity keeps rising

    Hi all,
    My trouble-free pool is doing great under the BBB method, in general.
    However:
    I have noticed that the TA is high (tends to want to be ~125-130).
    I add acid. Ph and TA go down, then I aerate to a higher pH-- at which point the TA is right back up there again.

    Here are a series of test results (CH constant at 270, CYA 46, FCL/TCL hovering 2.0-4.0 as I add daily bleach):

    day 1: pH 7.6 TA 134 => add acid
    day 2: pH 7.0 TA 89 => aerate for a day
    day 3: pH 7.3 TA 84
    day 4: pH 7.4 TA 125

    It's as though there is a source of alkalinity; like my 4-year old plaster is still curing, or something.
    Is this a problem? Or do I just keep adding acid?

    Location: Media, PA (Philadelphia suburb).
    In-ground, 13,000 gallon pool, plaster, built 2008-9.
    Pump Whisper-flow 60 gpm DE filter
    Spa: 2013 Hot Springs/salt generator

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    coffeegoddss's Avatar
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    Re: Alkalinity keeps rising

    I don't know about the plaster but have you tested the water you put into the pool? I battle high TA and, for giggles, decided to test what comes out of the hose. The TA was 290! So every time I top off the pool an inch or two, I'm adding to the TA. It's a never ending battle - but I think I've finally gotten it under control. Now that I know what's causing it, I can correct it pretty quick.
    AG, 10,400 gallons, filter cartridge, 2HP pump
    Coffeegoddss...bonafide thread killer!
    POOL SCHOOL...fortheloveofgawd, read POOL SCHOOL

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    JasonLion's Avatar
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    Re: Alkalinity keeps rising

    Have you been adding water to top off the pool? Fill water is a common source of TA in some areas.

    Lowering TA is a fairly slow process. Give it time and it will work.

    Also, what test kit are you using to get those test results. None of the tests which give results +-1 are actually any where near as precise as they imply that they are, and you actual levels are likely to be noticeably different than the results returned by those tests.
    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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    Join Date
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    Houston, Texas
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    Re: Alkalinity keeps rising

    Similar issue here. Just this week my TA went from 50 back up to 70 over a 5 day period with NO added water. I wonder if a temporary drop in TA is normal after an acid addition? My TA will always drop 10 to 20 ppm about a day after an acid addition. Two or three days after that it's back up, but it does not continue to rise above 70. I can't imagine it's a problem with my circulation. With my 2 HP pump I get a complete turnover every 1.5-2 hours.
    9,200 gal. Gunite Luna Quartz French Grey pool with spill over spa, two fountains on tanning ledge (rarely used)
    Pentair Whisperflo 2HP, Pentair CCP Cartridge 420 Sq. Ft., Polaris 280 with booster pump
    Pentair EasyTouch 4, RayPak LoNox 266k Natural Gas heater, Aqua Rite SWCG T Cell 9, Borates, TF-100 test kit

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    JulieS's Avatar
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    Michigan
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    Re: Alkalinity keeps rising

    I just asked this same question in another thread! I am not adding water at all, once my TA is in range, a day later it is back to 170-180. The TA of the water I used to fill is 270, but once I get it down, shouldn't it stay down? I understand that if I add more water it will go up, but with just normal conditions it shouldn't... right?

    I have had to back fill one time, I used a standard garden sprinkler to aerate as I filled, it helped bring my pH up so that I could add the acid to lower the newly raised TA!
    Intex AG Round 15'x42" About 4600 Gallons.
    2650 Gallon Sand Filter Pump W/GFCI .
    K-2006 test kit.
    Here in the beautiful Southwest Michigan!

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    Re: Alkalinity keeps rising

    To all who replied,
    Thanks.
    I will test the fill water, should have thought of that.
    But, in the above series of test results, no water was added.
    My tester is the Lamotte ColorQ.
    Location: Media, PA (Philadelphia suburb).
    In-ground, 13,000 gallon pool, plaster, built 2008-9.
    Pump Whisper-flow 60 gpm DE filter
    Spa: 2013 Hot Springs/salt generator

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    Join Date
    Oct 2007
    Location
    Valrico, FL
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    537

    Re: Alkalinity keeps rising

    I have noticed that if it rains after a period of dry weather, the TA in my pool will increase. I believe it is the dust and diry washing off of everything.
    7,500 gal, IG pool, L shape 22' x 15', 1.5 hp pump, cartridge filter, AquaPlus SWG/Controller, Pebble-Tec liner.

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    JasonLion's Avatar
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    Re: Alkalinity keeps rising

    The ColorQ's alkalinity test is +-15 in the relevant range when everything is working correctly.

    I suspect the Day 4 result might be wrong. It will be interesting to see if that increase continues or the number drops down the next time you test 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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