Why doesn't anyone like UGFs? They are great for smaller tanks. They can hold loads of bacteria. Basically turns all of your substrate into a mechanical/biological filter. I would even say that the UGF has 3 to 4X the amount of surface area compared to the two filters that come with the 55 . It is old technology, but that doesn't mean it does't work. I don't know how many stores I've seen running of just UGFs.