Education
At the 1970 European Aquatics Championships he finished in sixth place in the 400 m freestyle.
At the 1970 European Aquatics Championships he finished in sixth place in the 400 m freestyle.
He is the divorced husband of two-time silver Olympic swimmer Gabriele Wetzko. In 1972 he competed in the 100 m, 200 m, 4×100 m and 4×200 m freestyle events. In 1976 he was part of the East German 4×200 m freestyle team that was placed fifth.
At the 1973 FINA World Aquatics Championships, Hartung competed in the 4×200 m freestyle relay and finished in fourth place.
In 1975, he was part of two relay teams: 4 × 100 m, in which East Germany got sixth place, and 4 × 200 m, in which his team finished fifth.
Born in East Berlin, East Germany, he competed at the 1972 and 1976 and won a bronze medal in the 4 × 100 m freestyle relay in 1972. The East German 4×200 m freestyle relay team, of which he was part, won the bronze medal. At the 1974 European Aquatics Championships his team won a bronze medal in the 4×100 m freestyle relay. His team won a bronze medal in the 4×100 m relay.