Single Tanks Softeners

All water softeners have a tank or cylinder filled with a special softening resin. When the resin becomes saturated with the calcium and magnesium (the cause of limescale) the tank is then regenerated with salt brine which recharges the resin with sodium and the cycle begins again. Single Tank Water Softeners, as the name suggest have only one tank. When this tank is being regenerated, it cannot soften the water which is why they are set to regenerate in the middle of the night when you are not using water.