How a softener works
Ion-exchange softeners swap hardness minerals (calcium and magnesium) for sodium or potassium as water passes through resin beads. The softener regenerates on a schedule using brine from a salt tank, flushing hardness to drain and refreshing the resin.
Correct sizing matters: grains-per-gallon hardness × household water use determines capacity, while peak flow rate determines the valve and tank diameter so showers don't starve mid-regen or mid-morning.