I have a DIY Auto Top off on the 180g. It has a fault. The float valve will becomes stuck im assuming from salt creep. This obviously is a problem because it allows all the fresh top off water (several gallons) to flow into my sump. Which will effect my salt levels, possibly over flow my sump, and stress out inhabitants in the tank.

Last night it emptied around 5 gallons into my sump.

Anyone else have a DIY top off or a suggestion on a better float valve?