Calcium bicarbonate is then processed by {HEAD ~ a cation exchange system} to produce {TAIL ~ soda carb} such that: 
Calcium bicarbonate is then processed by { HEAD ~ a cation exchange system } to produce { TAIL ~ soda carb } such that :
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH