Would you please explain how UV cures and prevents ich in a single tank? I know UV will prevent transfer of ich from one tank to another, in a mult-tank system. This will be effective only if all water passes through a UV fixture between the tanks. This fixture must be of proper flow and maintained. However, in a single tank; if UV is to work on ich, every single free-swimming parasite must pass through the closed UV system before it finds a fish host and continues to multiply. The free-swimming form can emerge from cysts in the substrate, LR, corals, even the filter media. The odds of every one of these parasites finding the UV intake before a fish host seems astronomical. There are several well-known authors, that I consider experts, that agree (Fenner, Goemans, Paletta, Burgess, et al). I've said this several times, but for many hobbyists, I believe UV actually does more harm than good; by giving a false sense of security, thus delaying real treatment. UV may help some ; but I don't believe it is capable of preventing or curing any parasite infestation. Maybe I'm missing something.