Roebic 32 oz. Septic Tank & Cesspool Bacterial Cleaner. It is a powerful, natural solution for cleaning sluggish septic tanks, cesspools, drywells, and drain fields. It contains bacterial cultures that restore operating efficiency and one 32 oz. bottle treats a 500-gallon capacity. This product is certified biodegradable by Scientific Certification Systems and biodegradability is achieved in 10 days.