I have used Carribean or "Florida" LR, obtained from a LFS and online, in my tank to add to my current LR. IMHO, I would not consider it for cycling a new tank. The benefits are that it is aqua-cultured and comes with a very nice variety of visable life (can be good or bad, depending). Because of this, a lot of the life may not survive the cycle. I would go with cured or uncured LR, such as Fiji, from one of the sources Mike mentioned. After your tank is up and running, go ahead and source out some top-shelf carribean to add to the tank.