Acclimating tangs

Hey guys and gals. Any,tips on acclimating tangs into my aquarium. I have a 250gal. 2 months ago i drip acclimated my sailfin n hippo and then floated them . they both got ich and the hippo died. I am going to try to add my last 2 tangs, a yellow and a hippo once again. I invested in a 10gal tank to quarantine but then some,people say that the size will just stress them even more. Any thoughts