These ring compounds are maintained in {HEAD ~ a concentration} of between 0.01 and 4.0 grams per liter of solution in {TAIL ~ the bath} 
in
These ring compounds are maintained in { HEAD ~ a concentration } of between 0.01 and 4.0 grams per liter of solution in { TAIL ~ the bath }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL