In order to cycle the tank you need a few things. First you need something that is "dying off" and you also need something that consists of denitrifying bacteria. For the die off, I would go with a piece of raw shrimp from your local grocery store. This will start to deteriorate if you just drop it in. As for the bacteria, you would be better off getting live sand and CURED live rock (uncured will have more die off, bigger swing in numbers during cycle). Live sand and Live rock will really help your cycle out, because they are already full of the bacteria that gets rid of the ammonia and other toxic chemicals. For your tank you are going to need roughly 60 lbs of sand and 60 lbs of rock (or more, I have 80 in my 55) in order to get things going in the right direction. For the sand, you could probably buy 10 lbs of live, and the rest regular sand as it will all be seeded and become "live sand" in a short period of time. For the rock, if you could get it all at once that would be great, if not then buy as much as you can afford, as every little piece helps. Hopefully you can get at least 20 lbs (there is a store near me that sells it for 4$ a lb). Definitely take your time and read all the threads you can about cycling a tank and running a fish only (FOWLR) tank.
NOTE: Dont get Crushed Coral as your substrate, whatever you do, dont make that mistake, it will cause nothing but problems later on down the road.
