If we want to use hard water in textile dye processing first off all we need to remove the hardness of water. There are two types of hardness

1 Permanent  hardness

2 Temporary  hardness  

          Temporary  hardness

1 Ca(HCO3)2 + Ca(OH)2 → 2CaCO3 ↓ +2H2O

2. Mg(HCO3)2 + 2Ca(OH)2 → 2MgCO3 +2H2O

     MgCO3 + Ca(OH)2 → Mg(OH)2 + CaCO3 

CaSO4+Na2CO3→CaCO3+Na2SO4

MgSO4+Na2CO3→MgCO3+Na2SO4

MgCO3+Ca(OH)2→Mg(OH)2+CaCO3

For above that we can see permanent hardness remove by the chemical treatment but temporary hardness is remove by both boiling and temporary treatmen.