Evan,

I suspect that there might be a slight loss of Cl that is not protected by the CYA, even though Richard (Chem_Geek) describes the SWCG operation somewhat as a "closed System". Ex-chemical engineers don't believe in "closed systems".

As Richard has mentioned, there are a lot of loose ends regarding the SWCG process that still need to be tied up. Your experience of rising pH is just one.

Pat