Automatic waterchange with top off design - please gimme some feedback

[mseepman]

The only thing that I would throw into the mix is that when you turn off the return pump, your sump will fill with some additional water from the display until the back siphon stops. At that time, the water level will most likely be over your walled off skimmer area and you will be doing a much larger water change that you originally planned. As such, you just have to make sure you have enough fresh SW available to handle this amount.