Rust Out softener rust remover chemically removes iron and rust build-up that coats the resin beds and fouls the softener. This iron build-up is not totally removed during normal regeneration of a water softener. Using Rust Out softener rust remover in a water softener will eliminate rust and foreign matter from the resin bed which increases the life of the softener and reduces rust staining on household fixtures and other surfaces. We recommend using the softener rust remover regularly as preventative maintenance to ensure the softening and recharging efficiency of the softener’s resin bed. Additionally, in applications where iron is present you can use our well water formula to fight annoying rust stains.