Summer is here, the most heard sentence is to drink more water! The importance of drinking water can tell you a bunch of things, but this water is not the importance of water. Here I will let you know more about water.
First let's first understand the hardness of water:
The hardness of water is usually expressed by the content of calcium carbonate in water. Internationally, one milliliter of water contains one milligram of calcium carbonate, which is called 1 ppm. Usually, the hardness of water should not exceed 25 ppm.
According to the content of Ca2+ and Mg2+ ions, it can be divided into hard water and soft water.
Soft water is used when the ion content is small (hardness of 8 or less), and hard water is contained in a large amount (hardness of 17 or more). Located between the hard water and soft water.
At the same time, hard water can be divided into temporary hard water (boiling can be removed) and permanent hard water (boiling can not be removed)
Next we need to know the connection between soft water and hard water and our lives:
In natural water, away from the city, unpolluted rainwater and snowwater are soft water; spring water, stream water, river water, and reservoir water are mostly temporary hard water, and some groundwater is high hardness water. Water with too high hardness may cause temporary disturbance of gastrointestinal function.
Drinking water with a hardness of 707mg/L-935mg/L will cause intestinal symptoms such as abdominal distension, diarrhea and abdominal pain on the next day, and it will return to normal after a week or so. This is also a cause of "unacceptable".
（Source：http://www.waterfiltersfactory.com/news/hard-water-and-soft-water.html）