I use a 72g. I personally like having a larger permanently running setup for QT, especially when it comes to wrasses and other fish that are somewhat difficult to throw directly into the tank transfer method. In between QT groups, the pods build a large population again which helps the next QT group have a steady food source as well. You can also keep corals and inverts in it, dose prazi without worrying too much and just let the fish get healthy and used to being in captivity without being stressed from other fish and without having to worry about ammonia (As long as you don't add too many too fast). I usually give them a few weeks in there, get prazi done with, then start them in tank transfer method afterwards. Other fish like tangs or others that I consider easy, I just go right to tank transfer and dose prazi during that.