The Waterpilot FMX21 from Endress+Hauser Inc., Greenwood, IN, is a submersible pressure sensor suited for measuring the level of sludge and wastewater. The device uses a capacitive pressure sensor to measure level and has a SS housing, easy-to-clean flush-mounted process diaphragm, and provides a 4–20 mA linear output with HART 6.0 superimposed on the signal, allowing you to adjust the range remotely. It carries KTW, NSW, and ACS drinking water approvals. You can clean the device without losing calibration. Applications include lift stations, thickeners, digesters, and sludge holding tanks.