Ph for SWG's question


Apr 17, 2008
I've always run my ph around 7.2 with no problems. Now that I have a SWG and have read the Pool School section on SWG water balance I see the ph reccomendation there is 7.5-7.6. I'm confused: I thought SWG's cause ph to drift up, so wouldn't one want to start in the lower acceptable range so that when the ph went up you wouldn't find yourself having to bring it down so much? Thanks for the help, I always learn so much on TFP!


Mod Squad
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In The Industry
Apr 1, 2007
Sebring, Florida
Sometimes, we tend to be overly specific. Generally, any pool pH in the 7's is fine so it is easy to say 7.5 as being perfect.

In other words, your pH of 7.2 is fine and that's probably where I'd target the lower end of my pH if I had an SWG. I would then let it drift to around 7.8 before bringing it back down to the 7.2 lower end.


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May 7, 2007
Silver Spring, MD
With a SWG, your PH will tend to drift up much more than it did when you didn't have a SWG. Maintaining a higher PH helps stop the PH from drifting. The rate of PH drift increases when PH is lower and when TA is higher. That is why we recommend a lower TA and higher PH when you have a SWG. If you try to keep the PH at 7.2 you will probably need to use a lot of acid, which is annoying and can cause other problems.

If your PH remains stable around 7.2, then just ignore everything I said.