Answer:Water hardness is the high amount of dissolve mineral or ions as calcium,magnesium etc in the water.

Now,

If i want to use hard water for my textile dye processing,1st i need to make this hard water into soft water through different reactions for good results.

Water can be hard in two ways. They are:

1.Temporary hardness and 2.permanent hardness. 

Temporary hardness:

Temporary hardness  is caused by calcium or magnesium hydrogen carbonet.

For making this  Temporary water to soft water, we have to  boiling this and make by using calcium reaction like

Ca(HCO3)2+Ca(OH)2→2CaCO3↓+2H2O

Mg(HCO3)2+2Ca(OH)2→2MgCO3+2H2O

MgCO3+Ca(OH)2→Mg(OH)2+CaCO3

Permanent hardness is caused by calcium or magnesium sulphate.

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 treatment