cubuffs, I forgot, I would wait around 3 months as to not disrupt any cycling process before adding one to a new tank
liontamer, there are several aquarium manufactures, Sanders, Red Sea, and Ultralife. Most hobbyists use the Red Sea.
You can get entry level units for 150 and up. You can ---- hot-tub units for even less if you find the right deal.
They work by passing a electrical current through a tube to which airflow is circulated, thus splitting the air molecules. In humid environments it is recommended you use an air dryer for greater efficiency, but I found on mine it was quite bothersome to continually recharge it bi-weekly, so I run without it.
This tube is generally hooked to the air inlet to your skimmer, or sometimes powered by an airstone to a seperate reaction chamber.
I also forgot earlier that an added benefit is they kill parasites like a UV will, and also bond with ammonia forming it to nitrite and they bond nitrite and form it to nitrate, so your chance of a spike is lessened with an ozonizer as well.
If you are strictly looking for disease prevention I think UV may still be better. However when you add up all the positives I think the ozone is better. I have no papers to document these results, only personal experience.
tony