I've read through all the old posts on this subject, and I know the answer will probably be "just keep adding acid and the pH WILL come down eventually."
Current levels (Taylor K-2006 with freshly purchased pH drops):
TC = 7
FC = 7
pH = 8.3
TA = 110
CYA = 40
CH = 250
Water Temp = 90
My tap water has a pH of about 7.5 (I'm in Phoenix, AZ so my auto-leveller adds tap water on a regular basis due to evaporation). Past six months the pH has really wanted to settle on the high side towards 8.0. But lately I have not been able to get it to come down from 8.0+ readings. I am using fresh HASA acid and I've added two gallons (four days ago and again last night, about 12 hours ago) in the last week and the pH is not budging.
I needed to go buy some bleach and acid at the pool store, so I let them test the water. They came up with similar results as the above, but they also check for Total Adjusted Alkalinity, and said because it was "80" I need to raise my TA. I told them I wasn't interested in the adjusted level because I use the CSI and not the old LSI index. I don't think I need to raise my TA.
How many gallons of acid do I keep adding before I say "something else is up here?" It just seems weird to keep adding huge amounts of acid and not seeing the color budge (in fact, this morning's test almost led me to believe it actually went up slightly). The pool calculator tells me I only should have to add about quarter to half gallon of acid to go from 8.3 to 7.5.
Finally, I don't have new plaster. It is a pebbletec finish that was done over 10 years ago.
Any suggestions would be be much appreciated!