Ozone is very tricky if it escapes into the tank. It will kill anything in your tank, in the right amount. The ozone generators I've seen for our hobby involve filters to try preventing this from happening and also try to control the amount created. Generally, they have not found a home in our hobby because of the dangers. UV sterilizers, on the other hand, are safe and kill pathogens as readily as ozone (they also increase the ORP). However, to do these things, you need a level one sterilizer, not the cheaper green algae killers.
I have such a UVS and am a big proponent of them. I never see disease of any type in my display tank since installing one ~15 years ago.