So I purchased a Powder Brown Tang over the weekend at a store that will remain nameless at this point. I had setup a QT earlier in the week as I was preparing to add to my reef tank. At the store as was between a Kole tang and the Powder Brown. I went with the Powder Brown because he was eating and the Kole was not. Once i got the tang home got him into the QT and feed him and he ate. My initial thoughts were just to observe and see if any issues presented themselves. Two days ago the fish started to look botchy on the body but no white spots. I started prazipro and it is seeming to be possibly getting worse. The Powder Brown now is only swimming in front of the powerhead and now I'm thinking it may be velvet. So the main question is how long to wait after using carbon to remove the prazipro can I start Copper. Thanks in advance for any advise.