Rid O’ Rust RR1 2X Strength Rust Preventer, 1/2 gallon bottle. Use Rid O’ Rust RR1 to prevent UGLY rust stains caused by irrigation well water. Apply the formula through American Hydro Systems injection or siphoning system to prevent sprinkler stains from well water forever. RR1 is used for water with a pH of 6 or greater and any hardness level. 1/2 gallon (64 Oz.) of RR1 will treat 125,000 gallons of water with 1 ppm iron. The water treatment specialists at Pro Products offer a wide range of solutions that focus on rectifying problems, testing, cleaning stains, and maintaining the performance of water quality equipment.