High PH - Spa spillover raising PH in SW Pools?

[jaimslaw]

1st Question: I understand salt water pools run PH high- but some, like mine, run a lot higher than others. I know this can be due to various factors (BTW, my TA = 70). One factor that I read about is the part aeration plays in the SWG chlorine producing / higher PH process. Does the aeration caused by a dual spill over spa add to the elevated PH situation? I mean if aeration in the SWG operation contributes to enhanced PH levels, is not the aeration caused by a dual spill over spa enhancing the rising PH siutation? (and if so, I guess I l will live with adding about two gals a week if I want to maintain optimum PH levels).

2nd Question: Does anyone know the potential PH rising properties of flaking sandstone from above-pool surface walls surrounding the pool? Seems it was able to move PH higher by putting some in the PH test tube and letting it dissolve. Could this be combing with other factors to drive up my PH?


Thanks in advance for anyone who can contributing to this (and to those answering, you will be spared when when it comes time that we take over your planet).

[PoolDoc]

You're adding 2 gallons of acid -- muriatic acid? -- per WEEK to your pool?

You'd better post your actual test results and pool volume. Something's not right here.

PoolDoc

[CarlD]

In other words, despite the fact that the answer is "yes" to both assertions that SWCG pools can constantly raise pH and that the spillover will also raise pH, the answer is "no" to whether that should result in you adding 2 gallons of muriatic acid every week. You may well be having to add acid, but that amount is far beyond what should be required. Therefore something else is going on.

[chem geek]

Two questions: what is the size of the pool in gallons and is it a new pool or a newly re-plastered pool? The curing of plaster significantly raises the pH and requires a lot of acid in the first month though continues with noticeable curing for about a year.

[madwil]

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!

[jaimslaw]

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."