Any time you use medicines in your main tank you risk losing everything but the rock and fish most of the time. As everyone on here will tell you, Q tanks are the only way to go.

There are a couple of medications out there that are reef safe and I don't believe mela or pima are in that group. Ruby Reef makes a line of reef-safe products that work fairly well when over-dosed and don't seem to damage anything. I would look them up if I were you and tell the LFS guy he needs to do some research before telling his customers to use it in a reef. I was in there and they were willing to sell me a wrasse that had a little suspect spot on it and a bottle of melafix. I told them I wouldn't ever recommend adding any medicine to a reef tank.

The company website says its reef safe, but after you dosed and everything closed up I would be very very very careful about using it if it had that kind of effect.