indoor pool with chronic low pH and high TA please help


New member
Jun 26, 2012
I have been fighting with a pool that always drifts acidic. I use chlorine tablets and I added borates hoping it would help. I am constantly adding sodium carbonate to adjust it. The pool is crystal clear, but the ph is always off. My current parameters are:

7.0 pH
130 TA
200 Cal. Hardness
50 Borates

We have to keep the pool covered with a solar cover to retain heat and prevent condensation issues. Any solution to my problem? I keep driving my TA out of range fighting my low pH. I have tried using muriatic acid to blow off the alkalinity but I drove it back up when I brought the pH back to 7.2. I have tried aerating by leaving the pool slide on, but never saw a difference in Alkalinity after several days. I already did a quarter water change once this year. Very frustrated. Please help! Thanks!


Mod Squad
TFP Expert
Apr 4, 2007
SW Indiana
Stop using the chlorine tablets. Assuming they are trichlor, they drive pH down. You don't need the CYA they add since your pool is indoors, and it could be high enough to make your chlorine ineffective.


TFP Expert
LifeTime Supporter
May 10, 2010
SW Louisiana
I also have an indoor pool and while my pH does not drop on its own, it does rise VERY SLOWLY now that I am using liquid chlorine (bleach) for chlorination (I use about a quart of acid per year), when I was using trichlor pucks I had similar problems as you are having, but not as bad, as I would have to raise the pH every month or so. My fill water (from a private well) is fairly soft with a CH of about 50 and a pH of around 6.8 the last time I tested it (was about 7.1 a couple of years ago).