Low pH

WestSidePool · Jul 6, 2011

For the longest time my pH tends to fall and maintain it's levels around 6.8 or so ppm.
If I aerate, or add borax I can get it back up to 7.2+ but within a few day's it falls back down.

What could be causing this, is it a problem, and how do I deal with it?

TA-70
CYA-50-70 (just added stabilizer on monday)

anonapersona · Jul 6, 2011

Are you using trichlor pucks?

CYA has an acidifying effect, see the Pool Calculator, Effects of adding Chemicals.

Puffin · Jul 6, 2011

As I understand it, the TA goals are good targets for everyone. But at the end of the day we need to make adjustment for our specific cases. If 70 might be too low for your situation. Try raising it gradually, to see if your ph stabilizes.

In my situation, I have a TA of 130 and my pH is very stable (no detectable change is more than a month). The only time its moved is when I've done something to it (like add CYA, and when I added borates)

I know that's higher than the recommendation, but I'm lazy. To lower TA, you add acid. To lower pH, you add acid. So, I just planned to kill two birds with 1 stone as when the pH needs to be lowered, I'll add acid which will also lower the TA. Sure this is a very slow process, but again, I'm being lazy. To my surprise, I've not need to lower my pH at all.

WestSidePool · Jul 6, 2011

No, I used liquid chlorine for the longest time, and just recently switched to a SWG.
I was trying to get my numbers in line for the SWG and everything seems to be holding except the pH.

It's possible it's the CYA causing it.
I just added 2 lbs monday like i said.

We also keep the solar cover on when it's not in use. Could this also contribute to the lower of the pH?

JasonLion · Jul 6, 2011

A solar cover prevents most of the usual PH increases that are common with a SWG.

If you have ongoing problems with PH falling, raise your TA level.

Puffin · Jul 6, 2011

I don't have a SWG (yet, maybe pool Santa will fix that), so I don't know if this is normal. Sounds like it might be, I know SWG cause the pH to drift up. Setting up your chemistry to counter that makes sense.

But what I can say is according to the pool calculator 2lbs of stabilizer in 21000 gallons water will lower the pH by .21

WestSidePool · Jul 11, 2011

Over the weekend I made myself an aerator out of PVC.
I used some of the ideas I saw while browsing TFP.

I was able to get my pH up in less than a day. :party:

I'll monitor it and see if it stays, drops or rises.