Hard water passes through the online media tank that contains resin beads coated with sodium ions. The calcium and magnesium ions are exchanged for sodium (or potassium) ions, thus softening the water. When the beads have trapped the hardness and need to be regenerated, the WS1 metered control valve charges them with the brine from the brine tank. As regeneration occurs, calcium and magnesium (hardness) ions are freed from the beads, replaced with sodium or potassium ions; and the system is ready to soften water again using the standby tank. Immediate regeneration for soft water 100% of the time.