In order to remove scale forming ions like calcium & magnesium from water, strong acid cation ion exchange resins are used to exchange the scale forming ions in order to soften water. After exhaustion the strong acid cation resin is regenerated with brine solution (sodium chloride). The brine solution is passed from the bottom of the unit and feed water is passed from the top to bottom, this is called as the counter current or up flow mode of regeneration. This technique gives good quality of soft water throughout the cycle.

The INDION NG series of auto softeners incorporate the proven technique of counter flow regeneration, pioneered by Ion Exchange (India) Ltd. This technique is ideally suited to treat water having high hardness. The flow of water during operation and the flow of brine (salt solution) used to regenerate the unit are opposite to each other. Treated water is produced with consistent, low residual hardness throughout the cycle.

INDION 220 (in sodium form) is used to exchange sodium ions for hardness forming calcium and magnesium, and thus produces soft water. At the end of each service cycle, the ion exchange resin is automatically regenerated with sodium chloride solution, after which the unit is ready for the next service cycle. Regeneration happens based on the predefined time cycle.

The NG series currently comprises a total of four models with four flow rate. The difference between these is in the total volume of cation exchange resins used