I just did the same thing. I moved my 72 bow six feet to the side and removed all the sand and all the base rock. Put all the base rock in my 55 gal sump/fuge and keep it running the whole time. Once new tank was in place and plumbed, I filled with water, matched temp and ph, and fired it over to get the system mixing again. Then pulled the base rock out of sump, and placed in new tank. Old tank still running with the majority of my rock and sps. Now I just wait:headwally: oh and I opted for bare bottom after moving old sand - pita, and never again lol.