Can't stabilize PH

[DerrikM]

I have been using the BBB method for several years with great results, however this year I can't seeem to regulate my PH. My pool is 12,000 gal, inground, plaster, Haywood cartridge filter.

Readings using drops based test kit are as follows:
FC = 5.0
CC = 0
PH = 7.8
TA = 100
CA = 750 ( I know it's very high, but refill water is 400, so it has always been high)
CYA = 50
TEMP = 84 degrees

PH will rise about .2 ppm per day. Last year and the years prior to that, one gallon of acid would last me more than a full season. I have already been through 3 gallons this year between the lowering of TA last month (low PH and aeration method) and PH regulation. I thought that lowering my TA from 140 would make a big difference, but it didn't.

Don't know whether this has any effect, but pool is 12 years old, plaster is quite rough and will probably be replastered after closing this year. I am totally stumped as to why PH is such a pain.

DerrikM
San Antonio

 

[Kinguni]

You need to lower your TA even more. I found last year that at a TA of 70 I was able to maintain a pH of 7.5 - 7.6 using bleach as my source of chlorine.

 

[Guest]

get your TA down and try and maintain the pH between a narrow window of 7.6-7.8

 

[PoolOwnerNumber9]

You could use a water softener to reduce the calcium in the water. Any local service will rent you a setup. Run your water through the softener until the calcium is where you want it. Recheck all of your chemicals and rebalance. Use a water softener to control the calcium in the fill water as well. This should help keep things right. The high calcium is causing scale, which causes your walls to be rough.