Made with up to 99.8% pure salt, this premium-purity softener salt has a uniquely compacted shape for extra hardness. Virtually 100% water soluble, it is specially formulated to resist mushing and bridging in the brine tank-helping to keep your softener clean and trouble-free. The Red-Out formula product also contains a highly effective rust remover which helps to prevent rust stains on laundry and household fixtures. Recommended for use in all water softeners.