Thats a loaded question if I ever saw one hehehe....
I remember talking to you about the appartment situation what ever happened with that?
Once you decide to get a larger tank (hopefully minium 55 gallon) look into a canister filter. They do both bio, chem, and mech. You can get one that I would reccomend Fluval 404 for $89.99 or the Magnum 350 Pro sytem for $89.99 from
Big Al's Online You can use any media with these filters as well. Such as Ammo blocks, carbon, peat pellets/grainuals etc.
Protein skimmers are mainly for saltwater tanks to remove the excess waste. Usually this foam that floats on the top caused by the salts, food, and wastes in the water.
-S42K