Softener salt, also known as ion exchange resin regenerant. Its main chemical component is sodium chloride (NaCl). Due to the daily maintenance of water softeners and the need for resin regeneration, it requires a purity of over 99.5% and is generally in the form of pellets. The most common water treatment technology is ion exchange technology. All high-end water purifiers use ion exchange resins, typically sulfonate-type sodium ion exchange resins. When untreated raw water passes through the resin, harmful impurity ions (mainly calcium Ca and magnesium Mg ions) in the water are adsorbed by the resin, achieving the purpose of water purification. As the volume of treated water increases, more impurities are adsorbed, and the resin's adsorption capacity gradually decreases. To remove the impurities adsorbed by the resin (mainly calcium Ca and magnesium Mg ions), sodium ions (Na) are used through a backwashing method to exchange and displace the adsorbed impurity ions (mainly calcium Ca and magnesium Mg ions), thereby restoring the adsorption capacity of the ion exchange resin. This process is also known as ion exchange resin regeneration.