You need an algae bloom on a new tank, to know it cycled. From my experience there are many things we can't test for on a new tank to determine bacteria have colonized and are really cycling ammonia to nitrate, obviously in reef we need the longer 3rd cycle of anaerobic bacteria to remove nitrates, but, I have found it's pretty safe to add my first fish after I see green algae on the glass. As others have said I think a UV is a great idea if you like crystal clear water. I'm not sure I agree that UV should be used as a front line against ICH, but, I'm sure that at slow rates (I run 150gph through my TT 36w UV) if ICH made it into your system, the UV will slow it down.
There is no substitute for QT your livestock, for lots of reasons other than just ICH.
Observe the animal for 30 days, does it look healthy, does it hide, will it add value to your display, etc. Some animals just can't survive the move from the ocean to captivity, they get sick, disease, etc, why introduce it to your DT.
Again the above said, the UV IMO is a great second line of defense with the added benefit of crystal clear water with less use of expensive and messy carbon.
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