Soft water and hard water (Water hardness)

Today, water is essential for consumption whether it is washing clothes, washing dishes, cooking, farming, fishing until drinking

What is soft water and hard water?

•   Soft water is water in normal conditions, less than or equal to the content of calcium (Ca²⁺) and magnesium (Mg^{2 +}) in water 50 mg / L such as rain water, distilled water.
•   Hard water is water with high calcium (Ca²⁺) and magnesium (Mg²⁺) in the amount of 150 mg / L or more.

Causes of hard water due to the degradation of organic matter on the surface layer and combine with water to form carbonic acid (carbonic acid) which is a weak acid, when flowing to come into contact with the alkaline rock layer especially the limestone layers, which contain calcium carbonate (CaCO₃) and magnesium carbonate (MgCO₃) as the main components It will dissolve limestone with water resulting in more Ca²⁺ and Mg²⁺ content, resulting in increased hardness. Hard water makes it difficult to bleach the soap, does not create bubbles, causing scale in the kettle. Power consumption and also causes gallstones.

 How to solve the problem of hard water?

1. Boiling, the heat will cause the hardness to precipitate into limestone.
2. Add lime and soda ash to precipitate.
3. Use alum as a coagulant to accelerate the reaction in flocculation.
4. Use a metal catcher such as EDTA.