Lowering TA without hours :)


Bronze Supporter
Jul 10, 2018
Good evening folks... So I am planning my strategy for my first full Ahhsome, Drain, Refill.
I have had the most stable tub when Ive gotten my TA down to around 40. Thats about the point where no level of aeration can raise my PH above like 7.7...
That said, it took me a LONG time to get there. Talking hours and hours. Add .2 oz of acid, check PH, in 30 minutes, PH at 7.9, repeat. over and over.
Now I didnt take good notes on how much I added, but it had to be 6+ oz over 5+ hours. Is there any other way to lower TA at a quicker clip?
Obviously next time I am going to document from a clean tub how much it takes to get me to my target, but I am desperately trying to avoid the time sink im about to endure haha.


Well-known member
Sep 10, 2018
Athens, Ohio
So the article stated that it was bad for plaster to add a slug of acid. I usually target taking it down to around 7.0 and it takes about three to four additions to get it there. I also noticed pool math tells you to add more when your ta is high and you are targeting lower. Can 3 ounces of acid added to the middle of a 350 gallon tub really affect the surface of the hot tub? Didn't seem possible to me but what do I know lol


Feb 2, 2014
Madison, WI
Water comes out of my hose at a TA of 230-250 so I do a significant amount of lowering each time I drain and refill my hot tub. It usually takes ~16 oz of muriatic acid to bring it down to the 50-60 range. To begin with I add 2oz at a time and recheck pH after 5 minutes. Uniformly the pH will be high at the early rechecks, like off the charts bright pink. So even if I’m overdoing it a bit on the pH lowering, the time of exposure to low pH is very short. I check the TA after every few acid additions, and once it comes down to about 100 then I start adding smaller aliquots of acid to avoid overshooting on the low side of pH. I can usually finish this in about an hour.