Diamond Crystal 40-lb Water Softener Salt Potassium ChloridePotassium chloride works in water softeners the same way that traditional water softener salt (sodium chloride) does, by replacing hard water minerals. The primary difference is that hard water minerals are replaced with potassium instead of sodium. Salt substitute removes hard minerals leaving soft water without the sodium Up to 99. 1% sodium free Recommended for all types of water softeners Keeps your softener clean and trouble free Low insoluble