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 exchanger tanks.
These containers contain a high-performance resin on whose surface the sodium ions are located. When calcareous 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 plant must regenerate. To do this, the exchanger container is rinsed with a saline solution, whereby the resin beads are again filled with sodium ions. The calcium and magnesium ions flow off and the resin is ready for use again.
During regeneration, an exchanger tank cannot provide soft 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. Not so the units of the JUDO i-soft series and the SOFTwell P and K: they have two exchange tanks. If one of them regenerates, the other one simply continues working.