How a water softener works
• The hardness of water depends on the concentration of calcium (Ca 2+) and magnesium (Mg 2+ ) ions in the water.
• It is measured by its total hardness (TH) expressed in French degrees (°f).
• 1 French degree is equivalent to 10 mg of calcium carbonate per litre of water.
• Water hardness is not subject to standards since there is no known toxicity for man.
Hardness indicator :
Range of total hardness :
- Softening not essential
- Softening advisable
- Softening recommended
- Softening essential
Guide to the hardness of water by region:
(Source: French Ministry of Health– DDASS Sise-Eaux)
• Water softening is a process involving exchanging calcium and magnesium ions, responsible for water hardness, for sodium ions.
• Ion exchange is performed using a resin (composed of small beads) initially charged with sodium ions.
• When this resin is brought into contact with hard water, the calcium and magnesium ions bind to the resin by taking the place of the sodium ions which were originally there. These sodium ions are then released into the water. This gives softened water.