Penicillin and foul smell.

[christ6.regan]

Help. The tank is an eighty gallon freshwater running on a bio-wheel for approximately three years. Instead of doing our old routine of a hospital tank we have dosed the full tank with penicillin. The smell is very, very bad. Two thirty percent water changes along with carbon filter replacement don't seem to be improving the smell but the fish have come back from extreme lethargy to normal activity. Have I killed the bio-wheel?