pH keeps rising...

[cruzmisl]

Hi All,
I have a 20k gallon vinyl IG pool and the pH keeps rising. Any ideas as to why? I had to reduce TA and was aerating a lot which is why it was rising in the first place but I stopped that about a week ago and it still continues to rise.
Here are my particulars

FC-3.5ppm (use a Liquidator with 5.25% bleach)
CC-0ppm
CYA-50ppm
TA-140ppm
pH-7.8 (was 7.2 four days ago after the addition of some acid)

Thanks,
Joe

 

[KurtV]

I think your relatively high TA is putting upward pressure on your pH. I 'd lower it to something less than 120 and see how your pH trends then.

 

[JasonLion]

If you have had any rain recently or lots of swiming that would raise the PH through aeration. I would take the TA down to 80 or 90, or you can let that happen over time as you keep the PH under control. PH can drift around for a number of reasons, though high TA seems the most likely cause here.

 

[cruzmisl]

OK, I'll try and reduce the TA further.