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Thread: Why am I having to add acid

  1. Back To Top    #1

    Join Date
    Jul 2010
    Location
    Houston,TX
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    Why am I having to add acid

    I have a 17000 gal pool with spill over spa, ozonator, jug dumping, 50ppm of borate. The pool looks great, perfectly clear but my pH keeps drifting to 7.8. I have some iron staining so am trying to keep pH a little closer to 7.5. I am having to add about a quart of acid every week to get the pH down to 7.5. It stays there a few days and drifts back up to 7.8. I could understand if I had SWG but I don't. What's up with my pool?

    On 8/23 FC 4, CC 0, pH 7.8, TA 150, CH 360, CYA 70, Added 1 gal of 10% chlorine, 1q 1cup of Acid. Goal is FC 5-10
    On 8/28 FC 7.5 pH 7.8

    TA is elevated I think because when we swim we run the waterfall. Since I live in swampy Houston I think CYA and CH will come down with all the rain we get. Trying not to do a partial refill because of the borates. BTW with the borates the water looks like glass.
    17,000 gal in ground with spa, wet edge surface, Paramount PCC 2000 in-floor cleaner,Pentair Clean and Clear Plus 520 Cartridge filter, 3 hp Pentair Intelliflo VS SVRS pump , waterfall with 1 1/2 hp booster, Del ozone Eclipse1 ozonator, puck feeder. Borates added 8/2/2010

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    Join Date
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    Central Massachusetts
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    Re: Why am I having to add acid

    The waterfall really doesnt have anything to do with the TA being high. Two things are contributing to your pH drift.

    1) Your TA is too high. You should try and get that down to 100 or so.

    2) The waterfall is aerating the water. Aeration will cause the pH to rise as well due to the outgassing of CO2.

    You should lower the pH to around 7.0- 7.2 with acid, then aerate the water to increase the pH. Keep doing this cycle until the TA is down to around 100, and the pH rise should stabilize.
    14,000 gallon IG, Vinyl. Hayward 3/4 hp superpump, Penatair IC40 SWCG, Pentair automation, Hayward sand filter, Aqua Comfort heat pump, Hayward 400k Lo-Nox LP heater.

  3. Back To Top    #3

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    Jan 2010
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    Central Valley, CA
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    Re: Why am I having to add acid

    **disclaimer: noob trying to help **

    bk406 posted while I was replying so condensed.

    My TA is down to 150 after a 2 gallons of MA and my pH goes from 7.2 to 7.8 in about a week without aeration.

    When you use MA for pH, your TA will slowly go down. You don't have to worry about different procedures.
    Garden Leisure Voyager 12x24 AGP, 7500 Gallons, Hayward Power Flo Matrix 1 HP pump, dual speed, Hayward XStream Cartridge Filter, 120 GPM,

  4. Back To Top    #4

    Re: Why am I having to add acid

    Do test your tap water to find out what the TA is. If it is high like mine (340) you will find that even small additions of tap water will increase TA some and that means you will need to continue to lower pH and TA with acid.
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

  5. Back To Top    #5

    Join Date
    Jul 2010
    Location
    Houston,TX
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    Re: Why am I having to add acid

    My waterfall is about 7 tons of moss rock, so the water flows over a lot of flat surface and gets pretty well aerated. If I lower pH to 7.0, how long would I have to aerate to bring the pH back up?
    17,000 gal in ground with spa, wet edge surface, Paramount PCC 2000 in-floor cleaner,Pentair Clean and Clear Plus 520 Cartridge filter, 3 hp Pentair Intelliflo VS SVRS pump , waterfall with 1 1/2 hp booster, Del ozone Eclipse1 ozonator, puck feeder. Borates added 8/2/2010

  6. Back To Top    #6
    Richard320's Avatar
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    Re: Why am I having to add acid

    If you run things so the water is really churning, a couple hours ought to do it. When I need to lower TA, I get the spa going 100% and sometimes even run the booster. The spa appears to be boiling, and I've dropped 30 ppm in as little as 5 hours.

    Lowering TA by this method will use just as much acid as the way you've been going, it's just faster.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  7. Back To Top    #7

    Re: Why am I having to add acid

    When I did this quick method to lower TA I always wondered after the fact if it contributed to the sand that falls off the moss rocks in my waterfall. I don't know how much depth of rock can decay away before the whole darn thing has to be torn down and rebuilt.

    So, mu suggestion would be to not run the waterfall, at least then you won't have that worry. Running the spa and the bubbles there ought to help a lot, as long as you keep the circulation going from the spa to the pool to keep it all mixing well.

    Or, just do it slowly, every time you test, add MA to get to 7.2 pH and circulating through the spa to take advantage of that spillover. TA drops by 10 points every 2nd or 3rd time I do that. Then of course when I add tap water it goes back up some.
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

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