If it is a wastewater lift station you may want to look at a Radar unit they have dropped in price dramatically to a point where they are competitive with Ultrasonic. Wastewater lift stations have a tendency to have a layer of foam or grease and the Radar unit will outperform Ultrasonic in that environment. Siemens has a 2 wire unit LR-200 I believe is the model, I have a few mounted in tanks that have a layer of foam with no incident.