...or is it?
So I've been used to about a 0.6 pH rise over each week. After Hurricane Matthew I lowered the water seven inches and only got two inches of rain, which means I had to add about five inches of water to the pool. After adding the water back in last Sunday, I ran a full test with the following readings (and associated notes):
CC 1.0 (probably from stuff blowing in during the hurricane)
TA 40 (I keep TA low because raising it to 70-80 seems to make my pH rise even faster)
CH 300 (down 50ppm after the added "fresh" water)
Notes: Added 40 lbs of salt, cleaned SWG and filter. Added 32oz by vol stabilizer to skimmer (in nylon in two 16oz doses), set SWG to 25% (was 15%) and started 4hr boost cycle. Added 5oz of Beautec.
I purposely did not add HCL/MA since I knew CYA would help keep the pH lower. Today I tested (sorry, I didn't do a full test, just pH - I'll do a full test when Jan gets back and I'm not managing the household by myself) and pH tested 7.8, so last week it raised about 0.2. I've had CYA at 40-50 because I started the pool two years ago with bleach. A couple of months ago I switched to SWG and never realized there should be a higher CYA for it...Not wanting to overdo it, I added 32oz thinking that should raise it to 50-ish and I can add more to bring it up to 70-80. According to PoolMath it should have raised CYA by 23 and lowered pH by .43 (which calculates the .2 rise since it's typically .6). I know it is typical for pH to lower when adding CYA, but will it affect my pH rise over time (long term), or just this week since it was dissolving?