Salt and its uses
Salt is essential for your water softener to work properly.
The main questions about the use of salt to optimise the efficiency and life of your equipment are set out below.
What is the role of the salt ?
The water softener contains resins in the form of small beads.
They remove lime from the water by exchanging the calcium ions in hard water with the sodium ions they contain.
Hard water percolates through the resin bed, emerging as soft water from the appliance.
Depending on water consumption, these resins are gradually saturated with calcium ions and become less and less efficient.
They do not need to be replaced. All that needs to be done is to regenerate them using salt water (brine) obtained from water softener tablets. During this operation, referred to as regeneration, the calcium ions fixed on the resins are exchanged with sodium ions.
What type of salt to choose ?
Salt originates in 3 ways :
- rock salt or mine salt (generally used for snow clearance)
- sea salt (used for all purposes)
- refined salt (widely used in industry and for water softening)
Only refined salt should be used for water treatment, as it is highly purified.
The salt must meet 3 purity criteria :
- Physical purity : the salt must not contain any insoluble matter that could clog the brine suction systems and foul the resins.
- Chemical purity : the active substance is sodium chloride. The salt must not contain any other unnecessary or harmful constituents.
- Microbiological purity : the salt must be free of pathogenic germs.
Different forms of salt for water softening are available on the market : tablets (flat or cylindrical) and granules.
Tablets must be compact, chemically faultless and dense. Tablets should not disintegrate in the salt tank.To optimise the output of the appliance (in particular ion exchange resin regeneration), the use of highly pure flat or cylindrical tablets with convex faces is recommended.
This type of tablet will allow better water circulation inside the salt tank and will accelerate brine production.
What do dissolution, brine and disintegration mean ?
The tablet produces brine when it dissolves.
Brine is a saturated salt solution (310 g salt per litre of water) required for the resins to regenerate properly.
Disintegration is the fragmentation of the tablet into salt grains that generate a salty paste at the bottom of the tank. This substance does not dissolve and obstructs brine suction.
What is salt for electrochlorination ?
Electrolysis of sodium chloride solution produces sodium hypochlorite (bleach), a powerful disinfectant mainly used in swimming pools. After destroying bacteria and micro-organisms in the water, the active chlorine is naturally converted back to salt through the effect of UV radiation.
The use of refined salt compacted into tablets is recommended as they will dissolve gradually and homogeneously in the water.
Is softened water equivalent to natural soft water ?
The naturally soft water that flows in some granite regions (the Vosges, Brittany, and the Massif Central) should not be confused with softened water. They have different mineral compositions.
Soft water not only has a low concentration of lime, but also of numerous other dissolved minerals, while softened water, with its lime removed, still contains the same quantities of other minerals in solution.
Can softened water taste salty ?
Softened water cannot and should not taste salty. In sodium chloride, used mainly for cooking, the salty taste results from the combination of sodium with chlorides. The sodium concentration is slightly higher in softened water, but the chloride concentration remains unchanged. As a result, there is no change in its taste.
Is softened water corrosive ?
Corrosiveness and aggressiveness of water should not be confused. The corrosiveness of water is not linked to its hardness. On the contrary, softened water, with the calcium removed but still mineralised, is less corrosive on metals than soft water which, for example, attacks zinc and lead in pipework !
Is softened water a health hazard ?
Numerous systems referred to as water softeners, often resin based, reduce the hardness of water by removing calcium and adding sodium.
Water specialists consider that softened water does not particularly increase exposure to cardiovascular disorders (heart attack or high blood pressure), cancer of the digestive tract or osteoporosises.
Moreover, the presence of sodium in the water is not harmful to health, particularly in the case of a salt-free diet, bearing in mind that water with a hardness of 30° TH contains 0,138 g of sodium per litre after softening. AFSSA (the French food safety agency) recommends a daily sodium intake of 2,4 g to 3,1 g.
What happens to the salt that was used for regeneration ?
The salt used for regeneration, displacing the calcium fixed on the resins, is completely eliminated with the last discharge down the drain. Regeneration salt cannot be found in softened water in any cases.
Does water thrown down the drain after regeneration pollute the environment ?
For a TH reduced from 30°f to 6°f, less than 40 g of salt are thrown down the drain in the course of regeneration, once or twice a week for consumption of 100 litres of water by one person.
Regenerating salts used in water softeners are highly pure food-grade products, some of which are NF inspected and certified.
What is the NF mark ?
The NF mark confirms the voluntary certification of products and services. It certifies that the product or service complies with safety and quality characteristics defined in certification standards.
It ensures the high quality of certified products and services. Moreover, the NF mark guarantees a constant level of quality, as certified production processes and marketed products and services are regularly inspected.