When I moved my 29 into my current 55 gal I used all new sand along w/ the 45 lbs. LR I already had. There was a minimal cycle- all my animals survived just fine. Replacing the sand is a good idea as that's were most of the nutrients and other nasty things tend to accumulate in SW tanks. All the fauna that's in your sand, ie. worms, pods, are also in the LR. They will quickly repopulate the new sand-except the nass. snails obviously, those will have to be manually transferred. Good luck w/ the change.
Sweet! I wanted to just make sure everything will be cool when I do the change. Its my first change over, so I'm sorry if I have a million questions!
Thanks a lot for all the help!