I don't remember but I think an Oxydator just makes oxygen, doesn't it?
I don't have one of those or a UV sterilizer even though many people seem to think that is the key to my success. It is my good looks.
I have not used my ozonizer in 5 months either but I want to hook it up even though I am fairly sure it has nothing to do with diseases.
I used my diatom filter just after I collected some seaweed and mud infused NSW 5 months ago but I also doubt that is the secret. (If it is, Get one)
As for diseased fish. I go to an LFS almost every week. I went to a huge one today and didn't see any sick fish. I wanted to buy something but they only had common things like angels, tangs, royal grammas etc. I need unusual, something I rarely see, something that comes in once a year and no one knows what it is and I don't care if it has spots, rashes or the heartbreak of psoriasis. But I didn't see any of those diseases or fish.
I have been buying fish since 1971 (freshwater fish since 1953) and I think they were in much worse shape then. A good hobbyist today should be able to handle any disease that they feel comes on a new fish. Me and Atoll never have problems with any disease and diseases are a non issue for us so we must be enigma's.
I think much of the problems comes from stress (quarantine gives the most stress) and I also feel the foods many people use are not the type to prevent or cure a disease. To me, medications (of which I have none) are also a cause for stress as all medications are poisons. If you take a fish that is in the middle or a nervous breakdown, then dip it in fresh water, which really screws up their osmosis working skin and I am sure burns their gills, then put it in a bare tank it is a wonder any of them survive. And looking at the disease forum, many of them don't.
So I am not sure it is the condition of the fish we get as much as the treatment we give new fish that pushes them over the edge.
I know most , OK all the people feel me and Atoll are either lying or in a coma but between us we have about 90 years of fish keeping experience.
Some, or even a tiny bit of what we observe is probably true. Just my pain and drug induced opinion of course and if you don't agree with it, you can go about your business and I will go back to sleep.