The chlorine or other soluble material within the bag or sachet is dissolved or subjected to {HEAD ~ a leaching action} in {TAIL ~ the liquid} 
The chlorine or other soluble material within the bag or sachet is dissolved or subjected to { HEAD ~ a leaching action } in { TAIL ~ the liquid }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL