Do it Water Softener Salt Cubes with Rust Remover, 40 lb. are specially formulated to prevent iron deposit build-up and protect your sinks, dishes, toilets, cookware, and laundry from iron and rust discoloration. These salt cubes feature rust-fighting additives that help maintain the cleanliness and efficiency of your water softener system. Highly soluble and 99.8% pure salt, the cubes are designed to eliminate common issues such as bridging, mushing, and channeling in the brine tank, making maintenance easier by eliminating the need for frequent clean-outs. Conveniently packaged in a ready-to-use 40 lb. pour bag, these salt cubes provide an effective and hassle- solution for keeping your water softener running smoothly. Model Number: 766436