Yeah it does look like there will be room behind it, but I wasn't sure with the floor frame layout what was going on. It'll also be tough to crawl between 10" centered joists, so you may want a crawl tunnel to get underneath, or like Caoboy suggests, a maintenance door from the rear would be idealCaoboy;2702206; said:If you look at the first post, the tank doesn't look square, but rectangular, and the last picture, the frame looks square...Maybe he's put down the frame and he's going to cut a door into the backside?