just rinse/clean it out real well. you can reuse most of the stuff except for skimmer, hydrometer etc, everything else is still applicable for a freshwater. you should invest in a large piece of driftwood from manzman he's a vendor here, that really makes the tank stand out.
actually you can fill the skimmer with bio media and still use it... i did this with the one i got from my old 220... was perfect for extra bio filter