DIAMOND CRYSTAL POTASSIUM CHLORIDE FOR WATER SOFTENERSA Low Sodium Alternative to Traditional Water Softener Salt. Potassium Chloride, Salt Alternative, for Water Softeners is a low sodium alternative to traditional water softener salts. Made with typical 99. 1% pure potassium chloride, these crystals contain low insoluble content to keep your water softener running smoothly. Diamond Crystal Water Softener Potassium Chloride is recommended for all kinds of water softeners. Potassium Chloride works in