Automatic waterchange with top off design - please gimme some feedback

[DiverDude]

I don't see anything inherently wrong with the design but (and I don't know if the apex can accomodate this) I'd suggest that you have to push a button or something when you add the salt to your mix tank. That would preclude you forgetting to add salt and having a bunch of fresh water added to your tank by mistake.

The ATO wouldn't cycle again until the button had been pressed, confirming the water for the cahnge was in fact, salt water.