I need help please! I am use to having bio wheels and now instid of bio wheels I have a flat one called a bio-fiber it is just the same size of the filter with carbon but it is a separate peice. So I am wondering if I have another fish tank that I am trying to find a bio fiber for that can lay flat in top of the lid and I am having problems finding one small enough to fit can I cut a peice off of the bio-fiber that came with my other fish tank and use it?