PH actually changed

cj133

Well-known member
May 6, 2018
198
NJ
I know this is discussed endlessly but I'm a bit confused and I'm sure someone may have an idea.

My tap water seems to always have a high TA. Usually around 180.
I used muriac acid to bring my TA and PH down at which point my TA stayed around 120 and my PH was solid at 7.6 for weeks. Nothing changed it, downpours, swimming etc the PH was a solid 7.6

We had a lot of rain and I dropped the pool a few times so the other day I added some CYA. I check my water the day after and I'm at 7.4. I checked it last night, same thing still 7.4.

I use a solar cover at night and often during the day if no one is going in. I didn't add much CYA, maybe enough to bring it up 5 ppm or so. My CYA level is around 30 right now.

Is the CYA the culprit here? Could a small amount have dropped my PH by 0.2 if my TA is 120?

And the most important question. Should I do anything other than keep checking it? I assume no.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
7,861
Northern NJ
CYA is a mild acid. I don't know how many gallons are in your pool or how much stabilizer you added but it will lower the pH a bit.
 

cj133

Well-known member
May 6, 2018
198
NJ
CYA is a mild acid. I don't know how many gallons are in your pool or how much stabilizer you added but it will lower the pH a bit.

Roughly 8500 gallons.
I probably went from around 25ppm to 30ppm. Worse case, 20ppm to 30ppm.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
7,861
Northern NJ
11 oz of stabilizer would raise CYA by 9.7 and lower pH by 0.18. Just about the .2 pH reduction you observed. Isn't chemistry wonderful and predictable!
 
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cj133

Well-known member
May 6, 2018
198
NJ
11 oz of stabilizer would raise CYA by 9.7 and lower pH by 0.18. Just about the .2 pH reduction you observed. Isn't chemistry wonderful and predictable!

It is,
That's why I wanted to ask because if there's something evil afoot I wanted to know. :p