Understanding the Water Softening Process

WATER SOFTENERS
Purchasing water softeners can be a daunting task with so many different manufacturers and varieties to choose from. Here we will explain the water softening process, and describe the various types of water softeners available and their function.

UNDERSTANDING THE WATER SOFTENING PROCESS
Water hardness can be evident as white "chalky" deposits on hot and cold water fixtures, soap deposits ("soap scum"), and rings around the bathtub. Hard water can make laundering clothing more difficult, and requires the use of more soap when bathing and cleaning. Water softeners act to remove the hardness, and levels of iron and manganese, from your water.

Water softeners contain a control valve, that directs water flow during the regeneration cycle, a resin tank that contains the cation exchange resin, and a brine (salt) tank that hold the salt used during regeneration. Sodium and potassium is found in salt, as sodium chloride (NaCl) or potassium chloride (KCl). Salt is commonly available at most supermarkets, home centers, or plumbing supply stores in 40 or 50 pound bags.

The water softening process is accomplished by a chemical cation exchange that replaces the calcium and magnesium in your water with a equivalent number of sodium or potassium ions. During the softening process, your household water passes through the resin bed, and the magnesium and calcium are removed. A given sized resin bed has a fixed capacity to remove hardness before it needs to be regenerated to full capacity in order to continue provide softened water (for example, one cubic foot of resin has the ability to remove 32,000 grains of hardness from your water). When the resin bed is nearing exhaustion, the control valve washes the resin bed, and draws salt containing solution from the brine tank through the resin. As the salt contacts the resin bed, the process of ion exchange occurs, and the magnesium and calcium (hardness) that was collected in the bed during operation is washed to drain. After a final rinse to remove the excess salt, the resin bed is again ready to provide softened water.

CHOOSING A WATER SOFTENER
There are many different types of water softeners available to the consumer, and selecting the correct one can be confusing. We’ll try to shed light on some different systems that are available, and hopefully make your selection process a little easier.

Metered Based Water Softeners
Most metered water softeners have a single resin tank, and separate brine (salt) tank. Water softeners have a fixed capacity (based on size) to remove hardness from your water. When that capacity is exhausted, the softener needs to regenerate in order to again provide softened water to your home or business. Metered 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 timer (clock) based softeners, metered units will lead to savings over time. There are basically two type of metered water softeners:

Microprocessor Based 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 on-board computer control. Using parameters that are pre-set by the user (capacity, water hardness, etc.), the computer determines when regeneration is required and initiates the regeneration process automatically.

Electro-Mechanical Metered Water Softeners
Similar to the microprocessor based softeners described above, electro-mechanical metered water softeners measure water consumption with a turbine that turns as your water is used. The turbine 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, and moves the water softener through the regeneration process.

Time Clock Based Water Softeners
Time clock water softeners are different from metered water softeners, as they regenerate on a calendar basis. They also generally have a single resin tank softener with separate brine tank - but do not measure water consumption, and only regenerate on the day-of-the-week as set by the user - you pick the day (or days) of regeneration. An electrical motor automatically initiates the regeneration process when the time setting is reached.

Twin Tank Water Softeners
Twin tank water softeners have two resin tanks and a separate salt/brine tank. Twin tank units are always metered (demand), using either an electro-mechanical metering system, or computer based microprocessor meter as described above. Twin tank systems always have a fully regenerated tank available on standby, and deliver uninterrupted 24 hour supply of softened water. During regeneration, water is first passed thru the online tank before entering the tank undergoing regeneration - regeneration using this pre-treated water helps clean the system and extends the water softener lifetime. These units are generally more expensive that the single tank units described above, as they are basically two complete water softener systems combined into one unit

We hope that this information helped you to understand water softening, and to select the correct water softener for your application. If you have any questions, or would like to know more about water softeners, please visit our site at http://www.caitechnologies.com.