I use UV in my primary QT tank. I don't do freshwater dips without suspicion of flukes, as they tend to be quite harsh on the fish. In general Prazi is so mild that it is the only med I use prophylactically, and with them in QT is often easy to administer and less risk to the fish than pulling it and doing a freshwater dip. I generally do prolonged (over 6 weeks) observational QT over heavy prophylactics but captive bred clowns are so hardy I wouldn't worry too much about medications. I haven't used them yet but lots of people are liking H2O2 dips. I haven't felt confident enough to use one on new fish when they first come in, figure enough stress from being shipped, though next time I get a fish from a LFS, I probably will try it. I hear the H2O2 dips are much more mild on the fish than freshwater dips. For freshwater dips I use RODI, and like said match temp and ph. Even then it still tends to stun the fish, so it's important to keep the fish swimming in the dip. I tend to sort of heard them around with a chopstick. I haven't had any fish die from a freshwater dip but had some that took a while to recover from it.
