I bought this rack used at a local reptile show. I was told they hold cb70 tubs and it came with ten of them. My problem is these tubs to work with this rack require lids I dislike lids alot. When I put the tub in with out a lid there is a giant gap. My question is do I have the right tubs for this rack? or if I do have the right tubs is there another tub that fits better lidless?