What is the reason for formation of Scale?

The main problem associated with the use of hard water in the different applications is scale.

Scale is a precipitate deposited on surfaces (e.g. inner pipe surfaces) that are in contact with water.  

          Scale is formed by degree of super saturation

• high saturation index enhances scale formation

          Ca2+ + 2 HCO3- CaCO3 + H2O + CO2

• Scale is formed by Temperature

          Increase temperature, decreases solubility of CaCO3 and enhances scale formation

•  Scale is formed by PH

           Increase PH, decreases solubility of CaCO3 and enhances scale formation