I have a SWG but my PH is dropping. My current TF100 test results are:
PH = 7.2
FC = 13
CC = 0
Borates = 50 (approx.)
TA = 70
CYA = 80
CH = 50
Temp = 85
So far this season, I have added 6 pounds of 20 Mule Team Borax to raise the PH. I have recently added CYA to bring it up to my target of 80. It has only been a couple of days since I added the CYA so I am still trying to dial-in on the correct setting for my SWG. That's why the FC is presently on the high side. I want to target a FC of 8 or 9.
I have read the extended test kit directions for the PH test and understand that the reagent is compensated up to a FC level of 10. When FC level is between 10 and 20, the test result is higher than actual. So, if I understand this correctly, I may have a PH of less than the 7.2 reading that I got today.
Since SWG's tend to cause PH to rise over time, I'm not sure why mine is dropping. The only thing different this year is that I am using a solar blanket. Could this have an effect of the PH? Also, since my borate level is already around 50, should I still use more borax to raise the PH?