Marine Holding Tank TreatmentLiquify Holding Tank Solids And Eliminate Sewage Odors Sewage odors from the head and holding tanks make for an unpleasant time on the water. Smelly waste builds up inside the black tank clogging sensors and slowing down pump outs. EcoStrongs Marine Holding Tank Treatment liquifies black tank solids eliminating sewage odors in the process. It uses billions of enzyme producing bacteria to break down and eat waste, fats, oils and greases, and toilet