Constantly rising pH.

linust

0
Feb 6, 2013
8
Seattle
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?
 
Many pools seem to seek a pH around 7.8, which is fine. I would first try to leave it alone, lowering it when it reaches 8.0 but only lowering it to around 7.5 or 7.6. You might be surprised at how long it stays in the 7's.

I have never used CSI as a parameter so I can't help.
 
Generally we don't agonize over CSI as long as you are keeping all your parameters within our recommendations. You can see them on this page. Pool School - Recommended Levels

I have a sheer decent which adds a lot of aeration to my pool. Thus my pH tends to rise and I bring it down with acid. When the TA gets around 50 I bring it back to 70-80 with baking soda.
 
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