Hey Heavyhook

My initial thought is that you are running the SWCG too high

In the process of turning saline water into chlorine, there is an extra hydrogen atom that has nothing to bond with, so it becomes gas and the aeration causes the pH to rise (do you see little bubbles coming out of the return?)

I'd say to reduce the SWCG output to 50% and use bleach to augment when needed.

A full set of chem #s would also help