I ran ozone on my old temperate tank.
The main reason I was using it on this particular tank was to increase the skimmers working capacity through raising the oxidation potential of the system. Since the fish I was keeping were highly active with reasonably high metabolic rates, and I was feeding mostly high protein food stuffs (chopped fish, mussels, prawns etc.) and the lack of a sump, I felt ozone was the best option to increase the "filtration" capacity of the tank.
Worked an absolute treat too, I remember doing an experiment by turning the ozone off for two weeks to see if it really was making that much of a difference. The skimmate changed within a day or two, from thick, dark, sludge like material, to a lighter, foamier material, giving me the impression this lighter material was less broken down, or less oxidized, than with running ozone. Water clarity deteriorated, and algae bloomed. I'll check later today to see what the exact model ozoniser I was running, as I'm off to work in a minute.