When is water considered soft?
If a water contains hardly any minerals or none at all, then water is considered soft. Calcium and magnesium react with dissolved CO2 in the water to form carbonates. These form lime and are thus responsible for hard water and water hardness.
Both rainwater and distilled water are produced by evaporation, which is a high efficient kind of water softening. During evaporation most of the insoluble impurities are left behind. Because solids cannot evaporate with it. Therefore, both contain hardly any minerals and have a low or no degree of hardness. By definition, a water hardness of 0 – 7 °dH, is considered to be hardness grade 1 and by definition soft water in Germany.
What is hard water?
Water from hardness range 3 with a water hardness of 14 – 21°dH, is considered hard water in Germany. A water hardness of over 21°dH is not so common in Germany and is considered very hard water. Such drinking water is in a lot of cases treated centrally, by the water supplier. This central water softener system ensures that the hardness of the drinking water is tolerable. It is also argued that not every household needs its own water softener, if you have a central water softener system. Merus have successfully treated groundwater in the Midwest in the USA. This has a hardness of 128 grains per gallon, which is about 120 German hardness.
This is what the EPA Federal Environmental Agency says about hard and soft water.
Surface tension
The surface tension is an interfacial tension. It arises between liquids and the gas phase. It is caused by the fact that water wants to keep its surface small. Hard water has a high surface tension. Which helps the wasp on the left in the photo to walk on water. Such wasps and similar light insects float because their weight is too low to overcome the surface tension.
In personal hygiene, this hard water bothers us, because the soap on our skin or the shampoo in our hair does not foam properly.
One of the main effects of dishwashing detergent is to reduce surface tension. This allows the water to get closer to the dirty dishes and make them cleaner.
The softer the water, the lower the surface tension.
Many may know the experiment from physics lessons in school, with the razor blade floating on the water. Here, too, the surface tension of the water is higher than the weight of the razor blade. If you add detergent to the water, the surface tension is reduced and the razor blade sinks to the bottom.
If you use soft water, tea and coffee taste more intense. The soft water comes closer to the coffee powder or tea leaves. The advantage here, soft water can absorb more flavors, the taste is more intense. Customers say they also need less powder.
Technical problems caused by soft water or hard water
If the tap water is hard, we all know the problems of lime deposits on the faucet, the shower wall or in the kettle. Limescale also builds up in appliances, pipes or heat exchangers.
Water that is too soft can lead to corrosion or even pitting in pipes. Distilled water is largely free of minerals. Water tries to supply itself with minerals, it gets them from metallic pipes, which can lead to corrosion. We had some cases in the past, especially with copper pipes, where corrosion damage had occurred.
Our Merus rings help in both cases. And solve lime problems as well as corrosion in pipes and machines.