Choosing controls

Find out what controls the regeneration cycles, how long it takes and how much water and salt are used for recharging. Be aware that even fully-automatic types require occasional refilling with salt. Several different methods are used, but the two main types are:

Timer controls -- Clocks or electronic timers automatically recharge the unit at a preset time and day, based on your average usage. This type may fall short if you have unusually large water usage on a particular day. They also waste sodium and water because they regenerate whether or not recharging is necessary. They usually do this in the early morning hours.

DIR controls -- A more sophisticated method, called demand-initiated regeneration (DIR) senses when the resin must be recharged, either electronically or with a meter that measures and calculates usage. A DIR system saves on salt and regeneration water because it doesn't recharge unless necessary. In addition, it provides for unusually large water usage when you have guests.