Quote Originally Posted by madwil View Post
also, how much sandstone is flaking off? is it dissolving in the pool, or mostly just chunks that get removed fairly quickly?
Sandstone can change ph, but only if dissolving- if whole chunks are in but removed before substantial dissolving, shouldn't make "much" difference...
I didn't use 2 gallons acid all last year, much less in a week!
My pool info: 11 year old 13K plaster pool/spa in good shape; (as mentioned, dual spill over spa) So. Calif. very hard water; TA 60-70; Conditioner 80; Salt levels 3200; Starite DE filter and Heater; 2 HP Whisperflo single speed pump;

Sandstone flaking off weekly - I would say total would be maybe a cup - maybe two pool wide (hard to estimate this) - could be that small pieces do get to the DE grid and slowly dissolve there (am going to seal the Sandstone next month). Am not adding a lot of fresh water, which otherwise would cause a PH bump.

I will add 1/2 gal on Saturday, then PH is up past 7.8 by Tues. ; add another 1/2, PH back up past 7.7 a feww days later - so maybe its more like 1 1.2 gallons over, say, a 10 day period.

I asked the question as to the aeration effect of a dual spill over spa (increasing the PH in SWG) and want to follow up with this question: is there anyone out there with a dual spill over spa / SWG set up in So. Cal (ie using hard water) that has no Hi/ PH problems? On several other forums, I have read plenty of posts about the SWG/hi PH situation; I am coming to think that those with a SWG and no PH problem has a pool configuration different from others, such that there lack of a rising PH problem is more a function of their pool's configuration as opposed to TA levels and the like. (I mean, my TA levels are low, but that "fix" does not work for me).

Thanks for any input/insight you may have as to some of my "theories."