Actually experiments have shown ich requires a fish host. Without a host they will die. So considering the life cycle of ich, 6 weeks of QT
or fishless display tank will make sure there is no ich in the system. (life cycle of ich is max about 30 days)
Ich doesn't enter the UV
sterilizer, it lives. Ich (theront stage) that doesn't find a fish host in 24 hours will die. The usefulness of a UV
sterilizer against ich is obvious.
The risk of ich cyst being carried on inverts, corals is small. But I don't think anybody has tried to place a probability on the likelihood. So you have to make your own choice whether to QT
inverts and corals. It depends on how difficult it is for you to QT
has other benefits, like being in a stress-free environment to recover from transport, instead of being dumped into the main tank where there are animals that will irritate them before they are healthy. The disadvantage is that if you bought snails to eat algae, there most likely isn't any in the QT
. You will have to feed them something else.