{HEAD ~ Automatic controls} for {TAIL ~ the chlorine} dispensing and backwash can be provided so as to minimize the operational effort required 
for
{ HEAD ~ Automatic controls } for { TAIL ~ the chlorine } dispensing and backwash can be provided so as to minimize the operational effort required
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH