Rutland Tank Shield Fuel Oil Additive 1 Qt. Application - 1 Pt. For 250 Gal. Size : 1 Quart Helps eliminate oil-tank rust-out and soot build up &amp; dissolves gum and sludge deposits Increases safety and oil burner efficiency Fights rust by keeping water and condensation out of the tank Add 1 pint per 250 Gallons of fuel after initial double strength "shock treatment"