thinking about it you could use this for an auto sparge. by just putting the floats on a adjustable pole on top of the mash.
it actually works quite well in the Areogarden keeping the level topped up to the exact setting you set it.
The bottom float turns on the pump when it gets low, and the upper float is only there as a fail safe in case the bottom float fails.
While watching the one in the Areogarden it only turned on for a few seconds at at time.
i dont actually like the way they wired there project box and made my own wiring in a larger project box which included a a on /off switch and a hot and switched socket which you plug the 12 volt transformer and the pump