So, today I went to my LFS and was looking at a 55 Gallon (All tall tanks) and she was also trying to sell a 47 Gallon. I asked if I could get a deal if I bought both and she offered me a very good deal. I want to give one of the tanks to my oscars to upgrade their tank size, the other I would like to go saltwater. I really don't know anything about it and I'm trying to make a specific checklist (exact item name) and price check to see if it would be feasible. So, assuming I have the tank/tank stand..what else is needed? If possible, I'd like to get items that work for the larger tank and if needed used in the smaller tank. I know I'd like to have as much filtration as possible....under the substrate and more, but then again I'm coming from a freshwater background. Thought I'd post this as I do some research and get back to my LFS on deciding if I want to upgrade my tanks.