Used Emperor 400 or New Filter

[RaeRoss]

I just bought a 46-gallon bow front tank off Craig's List. She had a Marineland Emperor 400 and the water was still sitting in it (the filter) when I picked it up. I have no idea when she got rid of the fish, but it is disgusting. Calcified build up that a razor blade is having trouble getting off. My question, is it worth the time and effort to clean this filter or should I spring for a new one? And if a new one is the better option, which is the best one for a BIG fancy goldfish and a pleco?

Plus, the tank is not too bad, just some tiny algae spots. I'm just worried about moving my fish into a used tank. Am I just being paranoid?

Please help, I need to get these guys out of a 20-gallon tank!!
Thanks!!