Automatic On/Off switch for aquarium sump pump

[Quasar]

So I am wanting to make a DIY aquarium sump as I am limited by space, now to do this I am going to run a normal canister filter as a pre-filter and send the return to a sump, and then have a second (separate from the canister filter) return pump to the display tank itself. However as you probably imagined getting the canister filter and second return pump to flow at exactly the same rate all the time might be a bit tricky, and this is where my question resides. Does anyone here know of a system that can turn the return pump on and off at certain desired water levels so that my sump never runs dry or over flows similar to a ATO system but for a more powerful pump?

 

[John Neuzil]

Hydros controller