I'd have to agree with Cancer Man. FBT are pretty messy and the tank needs to be designed with easy cleaning in mind. I don't think there is enough water in the tanks and the thorough cleaning you have to do each time would pretty much kill the biological process. If i were to set up the ideal FBT tank I would completely separate my land section from my water section with a divider. I would have a drain on the bottom of the water section where the water could be emptied quickly. I would not put any gravel in the water section just a few larger stones so it is easy to clean. I don't think a waterfall is necessary but its up to preference. If you were going to do a waterfall I would use one of those that has a small filter that would be easy to change.