System Hydrus Duplex softeners are two filtration column. Each column has its own control unit is a separate module. This principle allows to increase system performance. The entire system is controlled by a single controller SmartStart. Both filtration column systems operate in parallel c sequential regeneration columns. It is possible to provide an arbitrary regeneration columns, but each column for this system should have its own controller. For regeneration using purified water, that improves cleaning quality, prolongs life of the system and reduces maintenance costs by saving water and salt.