Unfortunately my holding tank got screwed uP by my addition of live rock so I had to place my yeLLow tang in a smaller tank... how long can i keep him there? I have a powerfilter running in it... :scratchch
He should be fine for easy a week or more depending on the size of the tank and the fish. Try not to feed him that much as that will add waste to the water. If you need to leave him in for over a week then do a small water change after 5-6 days.