I put a new vinyl liner in my pool at the beginning of September. I'm still trying to get the TA in line. (I'm not yet using BBB, but plan to for closing and next summer. I hadn't heard of BBB until after I had the pool filled, and had started chlorinating with lithium shock and trichlor.)
My starting TA (tap water) is over 300. I've finally gotten it down to 140. I've been aerating for several days, and have been keeping pH between 6.8 and 7.8. When the pH gets above 7.5, I add more acid. Typically this drops pH to 6.8 or 7.0, and a few hours of aerating brings it back to 7.0 or 7.2. It takes quite a bit longer to get from 7.2 to 7.5 than it does to go from 6.8 to 7.2.
The recommendation in Pool School for TA in a vinyl, bleached pool is 70-90+. OK, how high is '+'? Is 140 an acceptable level or do I need to bring it down further? What's the impact of high alkalinity when closing, and is 140 actually high?
As of this morning:
CH - 200
pH - 6.8-7.0
TC - 5
TA - 140
CYA - 80 (this number is actually a few days old. I didn't test this one this morning.)
These numbers are from an HTH drop kit. I don't have my TF100 yet
So far, I've added about 10lbs of dry acid, and 2.5 gallons of MA. Based on the current rate of change, it will probably take another 1-1.5 gallons of MA (and another week) to get under 100.