I recently purchased a steel stand for my 55 gal of craigslist. Very sturdy stand. However, upon getting it home I realized it was sized for a 75 gal (48" x 18"). 6" too wide front to back. Can I put a piece of thick plywood on top and still use it for my 55 gal? should I add foam under as well? my 55 gal has a plastic frame.