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Thread: pH lowering

  1. Back To Top    #1

    Join Date
    Jun 2007

    pH lowering

    I have just a curiosity question. Yesterday my pH was at 8.0. I was a little worried that I had it too high. My TA was at 110. Today, my pH was about 7.6, and TA at 100. What makes the pH and TA lower that much from one day to the next? I know from what I've learned here that bleach will raise the pH, right? yesterday's TC was 5.5, today was 2.5, so could that make the difference? I was under the impression that if I got TA up to 110 that it would stay there for a while, keeping the pH from fluctuating.

    Just when I think I know all this stuff like the back of my hand, I realize there's a ton more I haven't learned yet!

    24 ft AG pool, Hayward DE filter, 1 hp pump
    Would insurance pay for a new pool if that big tree fell in it?

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: pH lowering

    Bleach has no long term effect on the PH, but it does have a short term effect. When you first add bleach the PH goes up. Then as the chlorine gets used up the PH goes back down. Normally, if you stay at a fairly uniform FC level, the PH stays more or less stable. But if the FC level goes down noticeably the PH will go down some as well.

    Higher TA levels have two separate effects. First, TA buffers PH from outside changes. The higher the TA the less effect acids and bases have on the PH. Second, TA puts upwards pressure on the PH, causing it to drift up over time. If TA is too high the PH will drift up annoyingly quickly.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  3. Back To Top    #3

    Re: pH lowering

    This thread might explain more than you want to know about TA!
    However, if you take the time to wade through it you will understand how it works!

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