If i close in September like my neighbors do, and open in May….that would be around 8 months …that amount of time with constant rising pH could make CSI wayyyyy out of wack.
You are correct, it is only temporarily high because I have been opening the cover every 4 or 5 days finding the pH as high as 8.6 and i end up adding Muriatic Acid to bring it down to about 7.6-7.8. From what I can tell, in this stagnant state, with a solid cover, with a center drain…the pH rises steadily at about 0.2 pH units per day.