The Level Gauge Cleaner repairs level sensors that fail due to tissue and sludge build-up. Dissolves waste, tissue, soap scum and prevents problems with regular use. Level Gauge Cleaner cleans probes in both grey and black water tanks. Its unique, enzyme-based, patent-pending formula is safe for all waste treatment systems. Design for the Environment recognized by the U.S. EPA! Approximately 1/2 bottle cleans a 40-gallon tank and helps keep level sensors working properly. 16 oz.