Hard water can typically be evaluated in {HEAD ~ terms} of {TAIL ~ its hardness level}, which is often reported in parts per million  
Hard water can typically be evaluated in { HEAD ~ terms } of { TAIL ~ its hardness level } , which is often reported in parts per million
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH