Quote Originally Posted by JimK View Post
Since adjusting my TA down a bit (about 80) a couple years ago I haven't had to add any acid at all.
Hey JimK!

I think for us it's the difference between vinyl and plaster. Vinyl pools tend to have pH drifts that are acidic whereas plaster pools drift alkaline. Therefore the alkaline drift caused by an SWCG can be balanced by the acidic drift in vinyl. For plaster that typically drifts alkaline, it's a compounding problem. I also get a lot of alkaline drift due to my rock waterfall and spa spillway running so it adds to the acid demand.

But I do agree that it helps to be on the lower side for TA to make the acid additions more reasonable. I also added 50ppm borates which helped to slow the pH rise but that also creates the need for larger acid additions to lower the pH. My pH is manageable but I just wanted to throw out the idea that SWCG's are not cost-free in terms of water balance.