A process and system are provided for treating fluid. In one illustrative embodiment, the treatment comprises the recharging of a resin bed in a water softener. A flow switch and accumulating timer are actuated when a selected flow rate is detected. The accumulating timer is set to a selected elapsed time. A chronological timer is also provided and is set for a selected time of day to recharge the resin bed. A reserve brine capacity is provided by delivering a selected amount of water to a brine tank at predetermined elapsed time intervals of the accumulating timer. The resin bed is recharged when both a selected elapsed time of the accumulating timer has occurred and it is the selected time of day.