I am obviously going to convert it to freshwater because...well let's face it, cichlids are the best fish on the planet.

Anyways I gave my fish guy all the fish and coral but keptall the rock and sand. I asked him about setting the new tank up and was telling him I was going to get rid of the rock and he told me that I can use the rock and the sand that came in the tank. (I transported it with about 10 gallons of water and about 100 pounds of sand. It took 6 guys to load in my truck.)
My question is has anyone else used rock from a saltwater tank with cichlids?
Also the tank came with a sump but it was under the tank in a home made stand and it is a bit wider than the tank and won't fit under the tank stand that actually is the correct size for tank. Having said that should I stick with the sump setup (in a smaller size) or go with a canister setup?
Sorry for rambling but I'm excited and I'm sure there will be more "long" posts to come.
Thanks