The term “hard water” when used in this present application is understood as {HEAD ~ water} that includes a variety of minerals or inorganic salts, particularly cationic alkali metal salts, for example, calcium salts, {TAIL ~ magnesium salts}, iron salts 
The term “ hard water ” when used in this present application is understood as { HEAD ~ water } that includes a variety of minerals or inorganic salts , particularly cationic alkali metal salts , for example , calcium salts , { TAIL ~ magnesium salts } , iron salts
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH