Nice! I built one of these two, derived from plans I found online. The electronics you can pretty straightforwardly automate with two water level sensors, a cheap motor, and a DC plug. I can dig up the links later, but if you go on yeggi.com and search you'd find the original.
The electronics is simply:
- 1 water level sensor inside the filter area, setup so when the water level rises it's _on_, triggering the motor
- 1 water level sensor outside the filter area, inverted, so that when the water level outside rises the circuit is _off_. This makes sure if you turn your normal pumps off and the sump water level rises, your roller doesn't spin infinitely
- 1 12V high torque DC motor to spin the filter
- 1 12V DC power plug to run everything
- 1 DC jack so you can plug things together
You then wire all of them together in series. Very dump circuit that does exactly what you need.