its all a matter of preference. i think bare bottom tanks look nice and sleek. i have a barebottom and siphoning the doo doo is a breeze during water changes. i have drift wood and a few ornaments for my fish and it looks good to me. the bacteria doesnt need substrate. it grows on the filter media and one of my filters is a penguin with bio-wheels so that works well for the bacteria. they might even grow on the driftwood and ornaments but i dont know that for sure.