Water softeners are designed to remove the minerals, calcium and magnesium that cause scale and scum. They are intended to treat the whole house supply, so they are installed close to the point where the water supply enters the premises. Water softeners have been used since 1903 to prevent scale in boilers, so the technology is well understood and their performance is predictable and reliable. They use a process called ion exchange whereby resin made of tiny polymeric beads trap calcium and magnesium, the cause of scale and scum in hard water. As water passes through the resin the calcium and magnesium ions swap places with the sodium ions in the resin. Sodium salts, unlike calcium and magnesium, are highly soluble so sodium does not cause scale or scum. When all the sodium ions have been exchanged for calcium or magnesium, the resin must be regenerated by recharging it with sodium ions. This is done by flushing the resin with salt solution (brine).
Water softeners are supplied in different shapes and sizes. All have a tank that holds resin where the water is softened and another to store and dissolve the salt for the regenerating brine. All water softeners regenerate automatically. There are various ways in which water softeners determine when to regenerate – some are fitted with a timer and some regenerate after a pre-set volume of water has been treated.
What are the benefits?
A water softener removes all of the calcium and magnesium, and are very effective in: