Constant rise PH, low TA HELP!

[central nj]

Hi,
Can I ask I beg for some help regarding my continually increasing pool PH? The plaster was replaced 1 year ago, I had it acid washed 2 months ago (scale staining I think).

Well, my PH rises at 0.1 every day, requiring 12 oz of acid daily. ChemGeek suggested that I lower the TA, and running the ph 7.6+. I did this, TA was 70, and over several weeks has drifted town to 50. Not much change in the acid demand in the pool. The other odd thing, is without any addition of water, my CH has risen from 280 to 320.

Should I be worried?
Is the pool still curing (and sort of recurring from the acid wash)?
I used the pool calculator--my csi runs a bit negative, should i go ahead and increase the TA?

Thanks!

Ph 7.6-7.9
TA 70 (now 50)
CH 320
CYA 40
Borates 50
FC 1-3
CC-always 0

 

[JasonLion]

Having both PH and CH rising is suggestive of either plaster curing or plaster being etched. Your chemistry numbers indicate that no etching should be taking place, which leaves us with curing as the most likely possibility. I wouldn't expect there to be any curing left after a year, but the acid wash would have exposed plaster that was deeper inside originally, and so would not have cured as quickly as the surface plaster and thus could still be curing.

You want CSI slightly negative. I don't see any problems with TA where it is. You could even lower TA down to 40 without problems.