Water softening is the process of replacing ions responsible for water hardness with sodium ions. Calcium and magnesium are exchanged for sodium. Sodium is obtained from brine, which is harmless to health. In case of softeners the bed regeneration process is based on several filtration cycles programmed on softening heads. The first stage is rinsing from the bottom – a process characteristic for every type of filter bed, not only for ion exchangers. The next stage is suction of brine, which consists in suction of brine solution located in the brine tank (solution tank for dissolving salt, in case of home softeners such a tank is incorporated in the softener in the form of so-called cabinets). Brine rinsing consists in running tap water through the column with the bed in order to clean the bed of excess salt which was not used in the ion exchange process and to remove calcium and magnesium ions. Adding water to the brine tank involves “topping up” the brine tank with a solvent (water) to create a brine solution. The maximum salt concentration in water is about 33%, and therefore the amount of dissolved salt is limited in relation to the amount of water contained in the brine tank. Individual stages of softener’s operation can be extended with e.g. additional bottom rinsing, top rinsing, partial regeneration process depending on water consumption (the device counts the amount of water which is needed for regeneration subtracting a part of water which would be used for regeneration of the bed which still has ion-exchange capacity).
