Getting ready for boric acid add. Pool calc said that I needed to add 3/4 gallon MA to lower pH from 7.8 to 7.2 or so while lowering TA from 90 to 60. Have spa overflow that I believve serves as a good aerator. About how long should it take for TA to reduce and pH to rebound? Boric Acid coming tomorrow and would like to dump it tomorrow night or Saturday morning if possible. Will be testing of course but about how long should I anticipate?
Timeframe for lowering TA and letting pH rebound?
- Thread starter firstbase
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first,
It takes me a day, or maybe two, depending on when I start, to reduce my TA from 120 to 60 or so. But this is not a one time deal. You have to do it every three or four hours until you get where you want to be. So, just as an example, not real numbers... If you add 3/4 of a gallon of MA, and it brings your pH down to 7.2, TA may only drop to 83. (I drop my pH to 7.0).. In about three or four hours pH will be back to 7.4, so you need to add more MA to drop it back to 7.2/7.0 which will drop the TA to say 75... etc. You have to keep this cycle up until you get the TA where you want it.
Jim R.
It takes me a day, or maybe two, depending on when I start, to reduce my TA from 120 to 60 or so. But this is not a one time deal. You have to do it every three or four hours until you get where you want to be. So, just as an example, not real numbers... If you add 3/4 of a gallon of MA, and it brings your pH down to 7.2, TA may only drop to 83. (I drop my pH to 7.0).. In about three or four hours pH will be back to 7.4, so you need to add more MA to drop it back to 7.2/7.0 which will drop the TA to say 75... etc. You have to keep this cycle up until you get the TA where you want it.
Jim R.
Thanks Jim. I appreciate you sharing your experience. I will check it later tonight after 5-6 hours and see what is up and then again in the morning or whenever. Go back and forth as you say until it stabilizes. Good to know that it is hours not days...I guess that is what I was questioning.
It takes way longer if you wait for it to go all the way back up to 7.8. The pH rise from 7.2 (or 7.0) to 7.5 is much faster than the rise from 7.5 to 7.8. You can save your time by re-dosing the acid when it gets to 7.4/7.5.