I run my SWG on a 26000 gallon above ground pool. It does a great job of maintaining the chlorine level. However I do have to add acid once per week to keep PH under control. I do have two returns on the pool managed by a three way valve. One operates the Aqualumiator/fountain pool light and the other runs a PoolSkim ahead of the skimmer. I really don't have any aeration going other than when we rarely run the fountain to cool down the water.

I've read somewhere of the chemical process that goes on that seems to explain the rise in PH. We are on a very alkaline south Texas well so all my fill water helps to contribute to that PH rise as well.