Oatey QT. Fuel Oil Sludge Treat is a storage tank additive that cleans and conditions fuel oil. It helps prevent fuel related heating system failure, improves combustion efficiency, reduces soot formation, prevents fuel oil waxing and gelling, disperses condensate water, helps avoid water blocked filters while cleaning strainers, nozzles, pumps and burners and minimizing burner breakdown. It prevents sludge build up and ice formation. QT treats approximately 500 gallons.