pH rising daily on new pool - Normal?


Well-known member
Oct 16, 2019
The Villages, Florida
I had a new pool installed, and it is now 2 months old. The installer did a low pH treatment 2 weeks ago to treat some spotting, and it worked extremely well.

Testing the water, I see my pH rising to 8.2 - 8.4 on a daily basis. I'm adding muriatic acid daily as recommended by Pool Math.

My test results are as follows for today:

FC: 4.0
CC: 0.0
pH: 8.4
TA: 70
CH: 375
CYA: 30 (should be receiving my cyanuric acid today to correct)
Salt: 3000

Is this type of rise normal for a new pool?
Last edited:

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Yes, new plaster can result in quicker than normal pH rises and can take several months to settle down. Continue to monitor it and adjust as necessary. Make sure as you continue to treat with acid and watch that the TA doesn't get too low as well (i.e. below 50).

FYI - Might want to confirm your CH. Unless that's a typo, CH results are typically in increments of 25, so I might expect to see 375 or 400 versus 378.


Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Very good. You said two things that put you in the driver's seat - using a TF-100 and the PoolMath tool. :goodjob: Just keep doing what you're doing. It may take a few months, but the pH spikes should slow down. I would mention that many SWG pools tends to find the upper 7s (7.7-7.8) as a stable pH area, but the PoolMath tool will keep you straight. Enjoy that new pool! :swim:


Aug 5, 2019
We had a new pool built in June and I also had a rapidly increasing pH. I was having to add 20 oz of acid almost daily just to keep it from creeping up too high. Keeping the TA lower around 70 helped limit the increase. After about the 3 month mark, it slowed down a lot. It was almost like someone flipped a switch, and now I'm adding just a few ounces of acid every week to keep the pH below 8.


TFP Expert
Mar 2, 2011
Increasing the Cya and lowering the TA should help.

Try to maintain the CSI between -0.3 and 0.0.

Be sure to brush the plaster regularly.