cause of high pH?

[ActivFam]

This am 8/5:
FC 7 ppm
CC 0
pH 7.8-8.2 (estimated color)
ALK 130
CYA 30
Water clear, temp 78 degrees

2 days ago (8/3) I noticed what appeared to be algae streaks on bottom of pool liner and ph was also 7.8-8.2. I treated high pH with muriatic acid and then I SLAMMED for algae. Thought maybe algae was due to high pH as FC has been within ranges. Pool liner is now clear again and have passed OCLT but pH has went back up today.

I can't figure out what is causing my higher end pH? ALK has been consistent all season, perhaps I need to drop lower and aerate to raise Ph? could it be air leak in cartridge filter? alot of circulation? air pollution? I'm stumped.

 

[mknauss]

Thought maybe algae was due to high pH as FC

pH has little effect on FC with CYA in the water.

pH rises due to elevated TA (you have that) and is enhanced with aeration. Pool use, wind, water features, etc create aeration.

 

[cowboycasey]

TA of 130 is causing your PH to rise fast.. drop it down to 80 or so and your PH will not rise as fast... You can lower TA fast by dropping PH and aerating to bring PH back up and dropping PH again.. It will do the same exact thing doing it slow over weeks... just depends on how much you want to work at it ..

What is the TA of your fill water?

 

[ActivFam]

Ok, thanks for confirming my suspicions. I'll lower TA and aerate to raise pH.
My fill water is high TA, which I usually don't have to do as we get rain, but not this summer so that's not helping.