The way the pool is plumbed thru the heater and jandy value and then off the slab I have no way of getting the cell between the valve and the ground, I have exactly 11 inches past the ball valve of all vertical pipe to where it goes underground. (unless it got really ugly and looped up or something, yuck). So I figured I could put the flow switch in the pool return and the cell before the jandy and ball valves. (I hope that makes sense). That would have same effect...all spa= no cell and not over chlorinate. Sounds like I for sure do not want the cell to run full power in just spa mode. So if I went with Total Control AP system it will not over chlorinate and adjust the Cl levels when it was just running the spa? (I knew it did the pH with acid but was not sure about Cl level, I guess that is the ORP thing). I really like the AP, plus it supports Sean a common supported/poster of my favorite pool site. Sean is it OK if I contact you off line to discuss cost options?