Ill get under there and take a better picture. And yes there is only the one small tank and another tank that's not permanently attached that came with camper. I can see the need for a pee trap definitely so I would need a little larger hole in the metal bed. The only way I could do this with a normal tank setup is to build a basement on bottom and make it flat all the way across, because of the way I will have to load it. This bed is wide and 24 feet long. I cant just back under it and then lower camper. Ive been pondering on this since Last November, and I need bigger tanks anyway, I need a flat Bottom so I can use peeler poles to roll it to the front off the truck once loaded. So far this seems like the easiest solution without doing some extensive modifications. The Cage is already mounted there on the truck. Ill try and get some good close up pics of the bottom of the camper. Maybe you guys will see something Im missing. Thank you for all the inputs, I need all the advise I can get.