Yeah I agree plus those guys are very knowledgeable but also very good salesmanA tank can be two years old and it’s still not considered a mature tank for keeping fish like the ones you have alive without QT.
BRS videos don’t really covert what a true mature reef is. It takes years and years to become one. I am talking sponges and microfauna and coral density and time.
Plan to QT or only buy from QT venders like Dr Reef and TSM from here on out if you want fish like this.
I have never personally done copper in a DT. I know people have and the used tons of copper absorbing media for a long time. I don’t remember how long off hand.