Automatic waterchange with top off design - please gimme some feedback

[Atomikk]

This is a similar design that I have in mind for my setup. I also have a similar controller (RKE) which can be programmed like the Apex. What I would do is time how long it takes for all of your syphon to break. Program that time, plus about 1 to 2 minutes into the Apex just before the it starts your pump in the sump. This would prevent you from dumping out too much water from the sump.