I'd highly suggest getting a copy of Robert Fenner's book The Conscientious Marine Aquarist. Your local club might even have a library that will allow you to check it out for a nominal amount and that way for the price of membership you'd get the membership and access to the book for a month or so. I think you'd do well to get a better grasp of the fundamentals of keeping a marine system and to have some local support as well as recommendations on where to shop.