When water contains a significant
amount of calcium and magnesium, it is called hard water.
Hard water is known to clog pipes and to complicate
soap and detergent dissolving in water.
Water softening is a technique that serves the removal
of the ions that cause the water to be hard, in most
cases calcium and magnesium ions. Iron ions may also
be removed during softening.
The best way to soften water is to use a water softener
unit and connect it directly to the water supply.
Water softeners are specific ion exchangers that are
designed to remove ions, which are positively charged.
Softeners mainly remove calcium (Ca2+) and magnesium
(Mg2+) ions. Calcium and magnesium are often referred
to as 'hardness minerals'.
Softeners are sometimes even applied to remove iron.
The softening devices are able to remove up to five
milligrams per litre (5 mg/L) of dissolved iron.
Softeners can operate automatic, semi-automatic, or
manual. Each type is rated on the amount of hardness
it can remove before regeneration is necessary.