Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 7 of 7

Thread: Muriatic acid, pH, and TA

  1. Back To Top    #1

    Join Date
    Jul 2016
    Location
    Carlsbad, CA
    Posts
    29

    Question Muriatic acid, pH, and TA

    I use bleach to chlorinate my pool, and I find that I have to add a little acid once or twice a week, as the pH rises. People in these forums have said that bleach should not be raising the pH very much, but I think in my case, it may be due to aeration, since my attached spa has a waterfall overflow into the pool. I find that my TA tends to slowly decrease (my tap water has TA of 100), so I occasionally have to add some baking soda to bring it back up, when it drops to 70 or less. I'm wondering if the aeration is causing this?

    (In my old days of ignorance, when I always used a chlorinator with tri-chlor tabs, I almost never had to add acid to control pH, but my TA would tend to slowly go up over time, so I sometimes had to use acid to bring the TA down.)
    16,000 gallon outdoor in-ground 16'x32' plaster pool (built 2002); Pentair Intelliflo VF pump; Jandy Cartridge filter;Rainbow in-line chlorinator (used only when I am away); Hayward 2 wheel suction-side pool cleaner; LARS gas heater, Taylor K-2006 FAS-DPD test kit

  2. Back To Top    #2

    TFP Guide
    Mr Bruce's Avatar
    Join Date
    Mar 2014
    Location
    Greenville, SC
    Posts
    1,798

    Re: Muriatic acid, pH, and TA

    Tabs are very acidic, so they were lowering your pH for you.

    You can let your TA drop to 50, see if that helps any. Yes, the aeration is what causes rising pH.
    32K gallon Plaster - 1hp Hayward 2 speed Super Pump - Hayward S200 Sand Filter - TF100XL
    Test Kits - Pool Math - Chlorine/CYA/Target/Slam Chart

  3. Back To Top    #3

    Join Date
    Jul 2016
    Location
    Carlsbad, CA
    Posts
    29

    Re: Muriatic acid, pH, and TA

    Quote Originally Posted by Mr Bruce View Post
    Tabs are very acidic, so they were lowering your pH for you.

    You can let your TA drop to 50, see if that helps any.
    How would that help? The usual recommendation is to keep TA between 80 and 120. I'm not too concerned about a TA of 70, but I just didn't want it to get too low. I've heard that pH can fluctuate more rapidly if TA gets too low.

    I don't mind adding acid a couple times a week. My pH increase is usually such that it gets up to about 7.8, and 1 drop of the acid demand reagent brings it down to 7.4. I'll then add the appropriate amount of muriatic acid which makes the pool pH go to 7.4, and then in about 3 or 4 days, it's back up around 7.8, at which point I add some more acid.
    16,000 gallon outdoor in-ground 16'x32' plaster pool (built 2002); Pentair Intelliflo VF pump; Jandy Cartridge filter;Rainbow in-line chlorinator (used only when I am away); Hayward 2 wheel suction-side pool cleaner; LARS gas heater, Taylor K-2006 FAS-DPD test kit

  4. Back To Top    #4
    bluetahoe's Avatar
    Join Date
    Sep 2014
    Location
    La Vernia, Tx
    Posts
    33

    Re: Muriatic acid, pH, and TA

    Quote Originally Posted by RGS View Post
    How would that help? The usual recommendation is to keep TA between 80 and 120. I'm not too concerned about a TA of 70, but I just didn't want it to get too low. I've heard that pH can fluctuate more rapidly if TA gets too low.

    I don't mind adding acid a couple times a week. My pH increase is usually such that it gets up to about 7.8, and 1 drop of the acid demand reagent brings it down to 7.4. I'll then add the appropriate amount of muriatic acid which makes the pool pH go to 7.4, and then in about 3 or 4 days, it's back up around 7.8, at which point I add some more acid.
    The experts here will tell you that it's ok to allow your TA to go down to 50 if that's what your pool "likes." Everyones pool is a little different and the 80 to 120 is a general rule. I keep my TA at 50 and it has been there for a long time and I still have to acid once a week as my ph still creeps up slowly-it doesn't fluctuate much at all.
    16x32 rectangular, 19,000 gal, gunite, quartzscapes plaster, Hayward Tristar 2 speed 1.5hp pump, 31" Hayward Pro Series sand filter, TF-100 test kit, BBB method rocks

  5. Back To Top    #5

    Join Date
    Jul 2016
    Location
    Carlsbad, CA
    Posts
    29

    Re: Muriatic acid, pH, and TA

    Thanks. I'll let the TA go to 50 then, and see if my pool likes it, instead of getting more baking soda. I was just concerned that if TA is steadily going down, at some point I'd need to stop it.
    16,000 gallon outdoor in-ground 16'x32' plaster pool (built 2002); Pentair Intelliflo VF pump; Jandy Cartridge filter;Rainbow in-line chlorinator (used only when I am away); Hayward 2 wheel suction-side pool cleaner; LARS gas heater, Taylor K-2006 FAS-DPD test kit

  6. Back To Top    #6
    bluetahoe's Avatar
    Join Date
    Sep 2014
    Location
    La Vernia, Tx
    Posts
    33

    Re: Muriatic acid, pH, and TA

    Quote Originally Posted by RGS View Post
    Thanks. I'll let the TA go to 50 then, and see if my pool likes it, instead of getting more baking soda. I was just concerned that if TA is steadily going down, at some point I'd need to stop it.
    Definitely give it a shot and see if that works better for you. Keep some baking soda handy just in case you do need to raise it at some point. You'll find the right spot for your pool.
    16x32 rectangular, 19,000 gal, gunite, quartzscapes plaster, Hayward Tristar 2 speed 1.5hp pump, 31" Hayward Pro Series sand filter, TF-100 test kit, BBB method rocks

  7. Back To Top    #7

    Join Date
    Sep 2016
    Location
    Magnolia, TX
    Posts
    38

    Re: Muriatic acid, pH, and TA

    Quote Originally Posted by bluetahoe View Post
    The experts here will tell you that it's ok to allow your TA to go down to 50 if that's what your pool "likes." Everyones pool is a little different and the 80 to 120 is a general rule. I keep my TA at 50 and it has been there for a long time and I still have to acid once a week as my ph still creeps up slowly-it doesn't fluctuate much at all.
    If I don't let my TA go down to 40-50 I have to add acid everyday and id be buying a gallon every other day. lol

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •