Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 11 of 11

Thread: How long to lower TA?

  1. Back To Top    #1

    Join Date
    May 2016
    Location
    Central Valley/ CA
    Posts
    28

    How long to lower TA?

    Apparently I let my water get out of hand this winter. I tested the other day and came up with:

    FC 1.0
    PH 8.2
    TA 140
    CH 550
    CYA 50

    Not surprising, I now have some scaling at the water line.

    Since then, I've gotten the PH and FC in check. I'm working on the TA with acid and aeration, but I'm curious how long it should take. The pool is about 25k gallons.

    Any thoughts?
    35,049 gal in ground free form pool, Jandy CL580 Cartridge filter, Jandy SHPF2.0-0 pump, Chlorine

  2. Back To Top    #2
    Mod Squad Jimrahbe's Avatar
    Join Date
    Jul 2014
    Location
    Bedford, TX
    Posts
    9,863

    Re: How long to lower TA?

    toby,

    I have a 17K pool and it takes me about two days, testing and adding MA every 3 or 4 hours to get from about 125 down to just under 60... I leave aeration on overnight but quit checking and adding about 10 pm and then start again the next morning...

    Why does your signature say your pool is over 35K???

    I'd also be looking at your FC as 1 ppm is way below the very, absolute, minimum to prevent algae...

    Thanks for posting,

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Caldera Spa.

  3. Back To Top    #3
    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    Location
    East Texas
    Posts
    10,188

    Re: How long to lower TA?

    A lot is gonna depend how effective your aeration is. Or..........how fast you can raise the ph.
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
    Pool Rover Jr., Pool Blaster Max, Diver Dave TF100 Test Kit/Speed Stir
    Margaritaville Frozen Concoction Maker, Liqour Chiller, & Drink Mixer & Party Tub----Collect 'um all!

  4. Back To Top    #4

    Join Date
    Sep 2017
    Location
    Silicon Valley, CA
    Posts
    464

    Re: How long to lower TA?

    Quote Originally Posted by Jimrahbe View Post
    toby,

    I have a 17K pool and it takes me about two days, testing and adding MA every 3 or 4 hours to get from about 125 down to just under 60... I leave aeration on overnight but quit checking and adding about 10 pm and then start again the next morning...

    Jim R.
    Jim, is there a temperature effect to this cycle? That is, does it take significantly longer if the water is 50 degrees versus 80 degrees?
    18Kgal play pool+spillover spa, Tahoe Blue Quartzscape refurb June 2017, ~40'x15'
    1.5HP VS JeP, CCP420 cartridge filter, Sta-Rite 400HD, 1.0HP VS JeP for sheer descents
    Caretaker 5-port in-floor system, AP1400 SWCG, Aqualink: RS-8 Combo, iQ20, One-Touch
    K-1005, K-1515 FAS-DPD, K-1766, Taylor 9056 comparator, SpeedStir!

  5. Back To Top    #5
    Mod Squad Jimrahbe's Avatar
    Join Date
    Jul 2014
    Location
    Bedford, TX
    Posts
    9,863

    Re: How long to lower TA?

    Dodger,

    I don't know... I have only done this in the summer...

    Sorry,

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Caldera Spa.

  6. Back To Top    #6

    Re: How long to lower TA?

    CO2 offgasses faster in warmer water, so lowering TA is faster in warmer water.

    Think about a Coke going flat. The warmer, the faster the process.
    Support the site

    Trouble Free Pool is a free resource. The people who answer questions are volunteers. If you find the site to be a good resource, please consider making a donation to help support the site. Thanks.

  7. Back To Top    #7
    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    Location
    East Texas
    Posts
    10,188

    Re: How long to lower TA?

    Same concept on beer!
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
    Pool Rover Jr., Pool Blaster Max, Diver Dave TF100 Test Kit/Speed Stir
    Margaritaville Frozen Concoction Maker, Liqour Chiller, & Drink Mixer & Party Tub----Collect 'um all!

  8. Back To Top    #8

    Join Date
    May 2016
    Location
    Central Valley/ CA
    Posts
    28

    Re: How long to lower TA?

    UPDATE

    So far, the TA has come down to 110. I've been adding acid when the ph gets to 7.5, bringing it down to 7.2. I have been running the pump with the return open for the 3' sheer descent for about 10 hours everyday. I noticed after not checking the ph or adding MA for two days, the ph only rose to 7.5. Does that sound normal? Is the sheer "waterfall" enough aeration?
    35,049 gal in ground free form pool, Jandy CL580 Cartridge filter, Jandy SHPF2.0-0 pump, Chlorine

  9. Back To Top    #9

    Join Date
    Sep 2017
    Location
    Silicon Valley, CA
    Posts
    464

    Re: How long to lower TA?

    Yea, that's why I asked about temperature effects. I was looking for anecdotal evidence.

    My pH is taking much longer to push up than it did last summer, even with the aeration devices running (sheer descents, spillover, floor system). I'm pretty sure the 50 degree water is a big factor in the slower pH push, because my other 2 pH-rise factors are:

    * SWCG, which is off for the winter and not contributing to push the pH up at all
    * newish plaster, which is now 8 months old, so probably not contributing at the rate it was several months ago

    I have ChemGeek's CO2 out-of-equilibrium chart bookmarked because I really like the concept it presents:

    https://www.troublefreepool.com/~ric...k/pool/CO2.htm

    This chart assumes 80 degree water. I haven't found the formula to see if temperature effects are linear, or more than or less than linear.

    But as the other guys say, one reason we like cold soda and cold beer is because the bubbles stay longer!
    18Kgal play pool+spillover spa, Tahoe Blue Quartzscape refurb June 2017, ~40'x15'
    1.5HP VS JeP, CCP420 cartridge filter, Sta-Rite 400HD, 1.0HP VS JeP for sheer descents
    Caretaker 5-port in-floor system, AP1400 SWCG, Aqualink: RS-8 Combo, iQ20, One-Touch
    K-1005, K-1515 FAS-DPD, K-1766, Taylor 9056 comparator, SpeedStir!

  10. Back To Top    #10

    Join Date
    May 2016
    Location
    Central Valley/ CA
    Posts
    28

    Re: How long to lower TA?

    Tested again tonight and TA was about 70. It took a couple weeks, but I wasn't adding MA everyday. Now to get the ring at the waterline off....
    35,049 gal in ground free form pool, Jandy CL580 Cartridge filter, Jandy SHPF2.0-0 pump, Chlorine

  11. Back To Top    #11

    Join Date
    Mar 2018
    Location
    Prosper, TX
    Posts
    60

    Re: How long to lower TA?

    Inserting myself to ask my own question... what is the mechanic that actually reduces TA? Is it the adding of the acid, or is it the rise in pH that consumes TA?

    Edit: Disregard, says it right here in the ole trusty dusty Pool School:

    "It is actually the acid which lowers TA. Adding acid lowers both the PH and the TA. Then aeration raises the PH without changing TA. Do not use chemicals to raise your pH during this procedure (unless your pH accidentally goes way too low); that will just raise your TA back up, which is exactly what you are trying to avoid."
    12.5k IG, non-SWG, 13'x30', Geometric, black pebble tec, tanning ledge/water feature, 2 main drains, 2 skimmers, 4 returns, Tristar VS Pump, Hayward Cartridge Filter (C4030)
    TF-100 + Speed Stir
    --------------
    Prosper, TX

Posting Permissions

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