|Best for: all dissolved ions - positive
or negative, including those which cause hardness, alkalinity, acidity, also
lead and other toxic heavy metals
May help with: sediment, turbidity
Not for: organic chemicals
For all practical purposes, deionized water is “pure” water,
as pure as distilled water. It’s good
for steam irons and car batteries and makes a great cup of coffee!
Deionizers are complete “ion exchangers”. In a deionizer, water flows through a
chamber filled with “cation” and “anion” synthetic resin beads. Millions of hydrogen ions (H+)
are loosely attached to each cation bead and hydroxide ions (OH-)
are attached to each anion bead.
Passing water exchanges all
its positive ions for H+ ions and all its negative ions for OH- ions.
Released H+ and OH- ions react with
each other, forming H-OH or H2O, which is water.
When deionizer resin becomes saturated with ions, it is
either thrown away or, in the case of large commercial deionizers,
“regenerated” with an acid and a base and used again and again. Water's ion
content is usually expressed as “total dissolved solids’ (TDS) in grains per