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Thread: Trying to Adjust TA

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    phalcon51's Avatar
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    Trying to Adjust TA

    My TA was a little high (about 90-100). Following the recommendations in the Pool Calculator I lowered the pH to 7.0 and began aerating the pool on Sunday evening. Yesterday morning the pH was 7.2 and today it's 7.4, but the TA went from 70 yesterday to 80 today. I understand that 80 is an OK level for TA, but is it normal for it to climb back up so fast? I thought the low pH brought down the TA and the aeration was supposed to cause the pH to rise but leave the TA alone. Is it likely to stabilize at some level below where it was to start with? Do I need to keep the pH at a lower level for a while, or just let it rise on its own to the normal range?

    Thanks

    Gary
    26,200 gal. 35' x 16' Plaster IGP (50 yrs. old), Hayward 48 sq. ft. DE filter, Hayward EcoStar VS pump, Intellichlor IC-40 SWCG, The Pool Cleaner 4X suction, Pool Skim and Pool Devil skimmers. Re-plastered Sept. 2010.

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    Re: Trying to Adjust TA

    The change in TA is either test error (one drop is 10 ppm) or small variation in the TA in different parts of the pool. Basically, when you add acid again to lower the pH back down to 7.0, the TA will get lowered. Continued cycling of aeration and acid addition will continue to lower the TA.

    If you're OK with 80, then you can just let the pH rise from aeration or on its own. If you want the TA to be lower than that, then continue the aeration and acid addition process.
    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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    phalcon51's Avatar
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    Re: Trying to Adjust TA

    Thanks Chem Geek.

    I'm OK with a TA of 80 so I'll just let the pH rise on its own till it gets to the normal range. I suppose the TA difference could be due to testing error, but I'm pretty meticulous about it. I always pull the water from the same spot in the pool and the same depth at the same time of day. I'm very careful to have exactly the right amount of water in the sample vial and put in the drops from a vertical bottle to try and make everything consistent. I'm also using a SpeedStir, but I suppose there can still be variations.

    Gary
    26,200 gal. 35' x 16' Plaster IGP (50 yrs. old), Hayward 48 sq. ft. DE filter, Hayward EcoStar VS pump, Intellichlor IC-40 SWCG, The Pool Cleaner 4X suction, Pool Skim and Pool Devil skimmers. Re-plastered Sept. 2010.

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    dmanb2b's Avatar
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    Re: Trying to Adjust TA

    Quote Originally Posted by phalcon51
    I'm also using a SpeedStir, but I suppose there can still be variations.

    Gary

    No doubt you can see variation of +/- 10, so it's not just you, but that said it is more than accurate enough and far more precise than test strip results tend to be interpreted. Your plan sounds just right
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

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