Snowbirding neighbor picked one up at Q last winter. It was a flow meter type thing. It worked OK when he was playing with it but only tempory mounted. With his plumbing and wires he had it wired near his pump. But to be real useful gadget he was going to install the meter where he could read it in his kitchen where other sensors and gauges were. And that was where he ran into problems, running the wires from pump to meter. Good idea but running the wiring takes some thought. His ran from zero and up and could also run backards from where he calibrated "full" for his size of tank and run to zero. If I remember right it was around $100.00 and manufacture was around Las Vegas selling from a web site and at RV type shows.