While virtually all modern water softeners utilize the ion-exchange method, the way in which the regeneration cycle is initiated differs. One method relies on a timer and the other uses a meter. These two approaches serve as the main water softening categories.
1. Time Clock Based Water SoftenersWater softeners that use the time clock method regenerate on a calendar basis. They do not measure water consumption, but rather regenerate after a specified number of days that you select. An electrical motor automatically initiates the regeneration process when the time setting is reached. While time clock systems benefit from simplicity, they can waste water and salt by unnecessarily regenerating the system during periods of low water consumption – while you are away on vacation or traveling on business. Time clock softeners also do not have the ability to respond to an increase in water demanded caused by a visiting house guests or catching up on laundry – which may result in hard water at the tap.
2. Metered Based Water SoftenersMetered units (also called "On-Demand") measure the amount of water consumption, and only regenerate when necessary. This saves both salt and water that is used during the softener regeneration process. While costing slightly more than time clock based softeners, metered units will lead to savings over time. There are two types of metered water softeners:
- Electro-Mechanical Metered Water Softeners
Softeners with an electro-mechanical meter measure water consumption with an impeller that turns as water is consumed. The impeller is connected directly to a mechanical water meter by cable. When the user-set gallon capacity is reached, an electrical motor is activated by a micro-switch, which moves the water softener through the regeneration process. - Digitally Metered Water Softeners
These softeners measure water consumption using a turbine that turns as your water is used. An electronic sensor detects the rate of turbine spin and sends a signal to the microprocessor control. Using parameters that are pre-set by the user, such as capacity and water hardness, the control determines when regeneration is required and initiates the regeneration process automatically.
More sophisticated water softeners with additional capabilities typically fall into the metered category. For example, twin tank water softeners are metered and differ from standard softeners because of an additional resin tank. These systems provide the added benefit of uninterrupted 24 hour softened water. This is made possible by the second tank, which regenerates and is available as a backup while the other tank is in use.
