I just did what you are talking about last weekend. So far I haven't lost anything.
Here is what I did:
1. Lay down new sand in new tank.
2. Put old sand on top to seed new sand and hold it down.
3. Fill with water ( I mixed 5 gallons of salt water at a time... took 3 hours to complete )
4. Let run for a day or so.
5. Put in rock (rock and corals were in old tank water in rubber maids )
6. Pick up sticks
7. Enjoy
I'm currently slowing increasing the light going to the corals. I went from 200w to nearly 800w so I figured it was a good idea.
Bryan Tacker - North Austin ( 620 and Parmer )
110g RR > 2x250w SE XM 10k with 2x140w Super Atinic > Matt Sump / Fuge > Red Berlin Skimmer.