I QT everything, including wrasses that need sand. I always keep one or two QT's going with sand and rock (not live, just algae covered) and treat all with Prazi and Cupramine. When I treat with Cupramine for the first couple of days I will have to add more for what is absorbed in the sand/rock, but after that initial period is stays fairly stable and once in a while I will have to add some Cupramine. Water quality in my QT's are not much different from my DT's. After treatment the tank gets a good water change and I then run carbon until I medicate again. If I have a delicate fish I may put in some live rock in the tank for the first couple of weeks to get the fish eating, remove the rock and then treat.