No qt here, it's just not practical (or wanted) in my apartment.
My 112g reef is 10 yrs old now and probably half of the fish I've ever bought were from petco (sorry if the P word is a bad word on R2R

. Some of them have been sick from various diseases and died within a day or two of getting them, but they never infect my healthy fish. I've even read from a mod on here that it's impossible to keep a powder blue tang long term in an ick tank. Well he should come over some time and see how old and healthy mine is.
Live rock, diverse bacteria, fresh seafood, and a stress-free tank are the way to go
Qt is fish torture, there I said it...