CYA and its effects on PH?

budysr

LifeTime Supporter
Aug 26, 2007
129
Pensacola
I am in the process of adding about 4 lb.s of CYA to get my level up where I want it. Seems like I recall somewhere on the forum(can't find it now) where the CYA will lower your ph? Sure enough as my CYA in a sock is in the process of dissolving, my PH that used to be perfect around 7.5,7.6 has now dropped to the low end of acceptable. Do I need to add some borax, or will the ph "correct" itself once the cya has fully dissolved and been in the water for awhile? I've been down this road last year but can't remember what I did, although I know I didn't ever add borax.
If it matters, my TA is good around 90-100
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
One pound of CYA has about the same effect on PH as 9.3 oz of muriatic acid. If your PH doesn't normally drift up on it's own you should go ahead and add some borax to bring the PH back up.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
The pH will drop as the CYA dissolves. If it bounces back up at all, it will be due to normal carbon dioxide outgassing from the pool and if you want, you can increase the rate by aeration. Otherwise, you can add some Borax to bring the pH back up.

[EDIT] There we go again -- Jason and I on a double tag team! [END-EDIT]
 

budysr

LifeTime Supporter
Aug 26, 2007
129
Pensacola
Thanks guys for the quick replies. I think last year when I added the CYA, I had the ph come back up on its own over time and it must of been from swimming, aeration. I am doing a little more CYA at one time this year so I guess the borax might be a good idea this time.