What exactly does water hardness refer to?
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The last edit to this post was made by Adventure Wang on 2016-8-9 at 02:46. It is said that the difference between softened water and desalinated water lies in their water hardness; but what exactly does hardness mean?
Water hardness refers to the content of Ca2+ and Mg2+ ions in water.
1 Demineralized water refers to the finished water obtained by using various water treatment processes to remove impurities in water such as suspended solids, colloids, and inorganic cations and anions. Desalinated water does not mean that all salts in the water have been completely removed; due to technical constraints and considerations related to production costs, trace impurities are allowed to be present in desalinated water depending on its intended use. The fewer impurities in the desalinated water, the higher its purity. 2 The hardness of water is mainly determined by the cations present in it: calcium (Ca2+) and magnesium (Mg2+) ions. When raw water containing hardness passes through the resin layer of the exchanger, the calcium and magnesium ions in the water are absorbed by the resin, while sodium ions are released. As a result, the water that flows out of the exchanger is softened water free of hardness ions. Once the resin has absorbed enough calcium and magnesium ions to reach a certain saturation level, the hardness of the output water increases. At this point, the water softener automatically carries out the regeneration of the saturated resin according to a predetermined program, using a solution of high-concentration sodium chloride (salt water) to restore the saturated resin to its sodium-form.
Softened water is water from which Ca2+ and Mg2+ ions have been removed