I'm interested in going with a salt water tank. My current setup is a FW 75 gallon tank with a Filstar XP2 Canister Filter. Is this enough to have a SW tank without coral, just fish and rock? Or do I really need a Skimmer? I would like to make it as painless on my wallet as possible. But if it is not possible, what would you reccommend as far as hardware? Such as, would I need a sump as well as a skimmer? Any help would be great. Thanks.