I was planning on how I will implement my ATO on the Reef-Pi. I don't know what sensor to use. I was planning to use a optical sensor to detect water level, and float switch as a backup (and a float valve)... The problem I am running into is that none of these switches are waterproof. So whenever I turn off my return pump the sensor will get wet and break... Should I just use a on contact liquid sensor? What are you guys doing?