Softening units work according to the ion exchange process. This means that they exchange the hardness forming calcium and magnesium ions, in the water, for sodium ions. This process takes place in the exchange columns.
These columns contain a high-performance resin on whose surface sodium ions are located. When hard water flows through the containers, the hardness forming ions displace the sodium and bind to the resin. The water is softened.
After a certain time, however, the resin is saturated. The device must be regenerated. To do this, the columns are filled with a saline solution, whereby the resin beads are again filled with sodium ions. Calcium and magnesium ions flow out and the resin is ready to use again.
During regeneration, an exchange column can’t provide softened water. If a softening unit only has one such container (so-called single-column units), it is inevitably out of service for a certain period of time. That’s not the case with the units of the JUDO i-soft series and the SOFTwell P and K: they have two exchange columns. If one of them regenerates, the other one simply continues working.