Had to add 2" to my pool to replace evaporation loss, so figured it was a good time to test my fill water.

Municipal supply, straight from the hose-

TC- .5 ppm
PH- 7.2 ppm
Alk- 320 ppm

The high alk really took me by suprise. Explains why I had high alk in my pool, and not matter what I do to lower it it creeps back up.

Tested the pool afterwards-

FC- 2 ppm
PH- 7.6 ppm
Alk- 210 ppm (had been 180 ppm).

I have an IG vinyl lined pool. Does it make any sense to fight the high alk? What is the recommended range of Alk for vinyl and what are the risks for running above the top end? PH seems stable between 7.6 and 8.0, so I choose not to fight it per Ben's recommendations.

I lowered alk to 150 about 2 weeks ago, PH dropped as well, then everything bounced back up. I've been adding .75 gal of 6% bleach nightly, pool volume is 21,200 gallons.