cause of high pH?

Jun 30, 2018
Minneapolis, MN
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.


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
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.


Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
Southern OK
Pool Size
Salt Water Generator
SWG Type
CircuPool SJ-40
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?
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