Outdoor Boiler Water Treatment Rust Inhibitor- ProTech 300 1 Gallon 128 oz Protect your wood boiler from rust, corrosion, and scale! Offers -3 Levels of Protection Meets or exceeds all boiler manufacturer nitrite warranty requirements. Balance pH and Alkalinity confidently Each one gallon bottle treats 300 Gallons at 1500 PPM Works with Stainless Steel, Mild Steel and Boiler Plate