Salt Chlorine Generators

by PHTA Recreational Water Quality Committee The purpose of this article is to provide a basic explanation of how electrolytic chlorine generators (ECGs) work. Electrolytic chlorine generators are sold for the treatment of swimming pools.


– Often referred to as electrolytic chlorine generators, electronic chlorine generators, saltwater chlorinators or saltwater generators (SWG) – Uses electricity and dissolved salt (typically sodium chloride) to produce chlorine for the pool – As with traditional chlorine sanitizers, the chlorine produced by the ECG yields hypochlorous acid in the pool – The chlorine that is produced sanitizes the pool water and destroys contaminants such as those found in sweat, urine and wind-blown debris – Properly sized systems reduce or eliminate the need for routine addition of chlorinating products – Produces chlorine only when the circulation system is operating – Other chemicals, such as balancing chemicals, algaecides, flocculants and metal sequestrants, may be required to protect pool surfaces and equipment and maintain water quality


ECGs work by converting dissolved chloride ions into available chlorine. Housed within the ECG are two types of electrodes called cathodes (positive charge) and anodes (negative charge). The electrodes are coated with a thin layer of a special metal called ruthenium, which is essential for the production of chlorine. As direct (DC) electric current passes through the cell, it generates chlorine gas which, when dissolved in water, provides a free available chlorine residual. This process does not result in the addition of stabilizer or balancing chemicals. Continued at the