Ron isn't that when the QT tank would/should become a "hospital tank" and the fish treated with hypo salinity or copper?
IMO that's right a QT tank should be a 24 hour hospital tank. There is much misunderstanding about QT tanks, so this is a great discussion guys. When I say QT some think about an isolation tank or holding tank. Unless it's undergoing precautionary treatment with copper, hypo salinity, etc, it is not a true QT tank IMO. Most do not QT there animals for 6 weeks, if they did I think we would indeed see a better survival rate out there. They opt for a basic isolation tank (untreated) set apart from the main display but even after the fish or coral serve there time in isolation they can transmit a pathogen or pest into the main system.
When I say I have seen them go from a true QT/hospital tank and develop ich, it was close to 6 weeks Amy more like 4 but again there may have been unknown circumstances that were responsible for that, it only happened one time so I don't know.
My main point is that these animals are brought into the country then usually after a very short rest shipped to a wholesaler and then off to the LFS. By the time you receive it the fish/coral has been in transit probably 3-4 times depending on country of origin and thats a lot of sress on the animal. A good wholesaler or transhipper will hold the animals for weeks before shipping them out to the LFS, bad ones could care less and that's why we see so many problems IMO.
If you want to set up a true QT system that's fine and prob wise but be sure to implement a full battery of antibiotics, antifungal, and sterile conditions or don't waste your time or money. If your serious about medication for your QT tank I suggest checking out No More Sick Fish.com for a full list of diseases, medications and precautionary meds.
Now Coral QT wow thats is another matter entirely, and I agree with Phil on this one. IMO this is more important than QTing fish, not because of coral health but rather because of the nasty parasites that can come from them. Red bugs, Montipora eating Nudis, zoapox just to name a few. These can be stopped from the start with some simple minor preemptive measures. Start by using your eyes and get to know your enemy. Once they get into a system they can wipe out entire colonies in a matter of days or weeks.