What you should know
Water hardness is caused by the presence of the dissolved minerals calcium and magnesium, often measured in grains per gallon of water (gpg).
When you have high levels of calcium and magnesium in your water, basic household tasks become difficult -- more scrubbing power is required, and greater amounts of detergents are needed to clean fixtures, clothing, and appliances.
How to Recognize Hard Water
The following are some of the tell-tale signs of hard water:
The method used most often in homes to remove water hardness is ion exchange water softening, in which positively charged hardness ions (magnesium and calcium) are replaced with sodium or potassium ions. This exchange of hardness ions for sodium or potassium ions takes place in the resin bed of the treatment unit during the softening cycle.
Benefits of Soft Water to the Consumer
Automatic -- An automatic water softener is equipped with a clock timer that automatically starts the regeneration process at preset intervals. During the regeneration process, the hardness ions collected in the ion exchange resin must be flushed out in order to allow the continuous exchange between soft and hard ions. The entire softening process is controlled automatically by the clock timer.
Demand Initiated Regeneration (DIR) -- Demand initiated regeneration (DIR) is the most efficient type of automatic water softener. Instead of regenerating at a preset interval, a DIR unit regenerates only when soft water runs out. DIR units use sensors or valves to determine when to regenerate. Because they adjust to the amount of water actually used, DIR units consume up to fifty percent less salt and water than do preset time clock automatic softeners.
Portable Exchange -- A portable exchange unit is a type of softener with a removable tank that is rented to a homeowner, and contains ion exchange resin that is fully regenerated and ready for use. When the resin material is exhausted (that is, when it is no longer exchanging hard ions for soft ions), the tank is returned to a central plant where it is regenerated and reprocessed to be used again.