Ok i am buying a house and it has a built in 60 gallon tank.. They left all the stuff with the tank. I want to put 3 oscars and one or 2 algae eaters. I need to clean the tank i heard do not use any chemicals so do i just use a rag and water? also what all do i need to do when i fill the tank up before i put the fish in? What is a good filter system for my setup that is not to pricey?