Since the hardness of water is mainly formed and expressed by calcium and magnesium, cation exchange resin (water softener) is generally used to replace Ca2+and Mg2+(the main component of scale formation) in water. With the increase of Ca2+and Mg2+in the resin, the efficiency of removing Ca2+and Mg2+by the resin decreases gradually.
The softening device is divided into five processes: working (sometimes called water production, the same below), backwashing, salt absorption (regeneration), slow flushing (replacement), and fast flushing. It is usually controlled by full-automatic multi-way valve or valve group.
