Utility Wonder 18-205 C.C. Rust-X Boiler Rust Inhibitor And Boiler Water Treatment. A hot water or steam conditioner prevents rust and corrosion, eliminates sediment accumulation and reduces the possibility of clogged controls. It's color coded to test boiler water conditions. It's periodic use keeps water crystal clear. Use Yearly At The Beginning Of Each Heating SeasonFor Steam Boiler Applications: Use One (1) Quart For Each 400 Square Feet Of Steam Radiation (96,000 BTU). If The Water In The Gauge Glass Has A Deep Red Tint, It Is Unfavorable For Efficient Steaming. This Can Be Solved By Using An Application Of Utility Wonder Dry Steam #3.For Water Boiler Applications: Use One (1) Quart For Each 300 Square Feet Of Radiation (72,000 BTU).