+1 for the Kole tang. I have one in a 75 and I absolutely love that fish. No, he's not as pretty as a yellow tang, but every bit of the hair algae that was starting in my tank was gone within a week. And he is constantly picking on the rocks, glass, and sand. He also begs for food when I walk up to the tank and when he actually sees the food can he goes NUTS. My favorite fish by far!
Hinds, if you want one then get one! Mine had a small case of ich, and I took all my fish out and did about a 3-4 week QT with copper and all is well. I didn't go the recommended length because they were starting to get stressed out in the 20L (2 clowns, kole tang, and yellow watchman goby) so I put them back in the DT. I've seen a little flashing, but zero spots. Just feed food that has garlic and the ich will stay under control.
And if you've quarantined all your fish, do the same with the tang and ich won't be a problem at all.