Like Bob, I pump a lot of water, I have three electric sump pumps and a fourth water powered all in the same sump pit, about 50 gallons. The smaller pumps are lowest then the larger electric, last the water powered. All four pumps have there float switches at different levels, activating an additional one as required. The lowest small pump may run three months in the spring without shutting off. Each pump has its own circuit. I also have a automatic backup generator. In my setup the float switches fail before the pumps. I am looking to replace a Sensaphone autodialer that is more compatible with cell phones.