Background: we bought the house in Feb 2013. In Jan 2013, just before we bought, the previous owner resurfaced the pool (plaster). As you can imagine during that time of year, the surface was not regularly brushed immediately afterwards (incredibly cold & windy)...not sure what impact that has.
For the rest of 2013 and 2014, I watched pH rise over 7.8 if I didn't add muriatic acid every 2-3 days.
After the heavy rains last month, CYA dropped from 50 to < 20. In prep for summer, I used tri-chlor pucks for a couple weeks to bring CYA back up to 35...that nicely kept pH down. Now that CYA is up to a reasonable level (leaving a bit of room for vacation this summer) I'm back to bleach...and pH maintenance: it is behaving the same as years past.
Here are most recent test results:
FC - 4.5 (maintain between 4 and 7 with 1 to 2 qts bleach/day)
CC - 0
pH - 7.8
TA - 50
CH - 225
CYA - 35
Water is crystal clear.
Question 1: Since baking soda is a buffer, would it help stabilize pH if I drive down pH to 7.2 then raise TA to 70 or 80?
Question 2: IF the pool has a natural tendency toward pH 7.8+, would I be better off managing CSI or keep chasing pH?