I change things around from time to time. I usually do it with a WC. Put 2 gal of water in a pot, place corals in there, then move my rocks around. I only have a 12 gal. I replce the water with fresh made SW, then I put my corals back where I want them. When I had my cown fish, I just kept him in there. He did't seem to mind.
I do turn off the lights for a bit.