[Myka]

Don't use ammonia, that's a FW method. All you need in SW is some live rock/rubble.

Just use the rubble as suggested above. Add your dry rock now too. That will give the bacteria time to seed the dry rock. Or instead of getting rubble just go buy some live rock. Let the rock and/or rubble and the dry rock sit in the tank until you're ready. That would be great. You could "feed" the tank a couple times a months with a small amount of flake (or w.h.y.) food if you want.