The Star brite 75032 is a 32 oz RV Bio Odor Enzyme Holding Tank Treatment designed for all holding tanks, including septic tanks in RVs and boats. Its bioactivated enzyme formula digests waste and paper, and it continues working long after initial treatment for lasting freshness. The treatment requires mixing 1 oz per 5 gallons of tank capacity with warm water and allowing it to sit in the toilet bowl for 30 minutes before flushing.