This is my first paludarium build, and I've got a 75 gallon standard tank. I'm about to sculpt a waterfall out of Styrofoam and then cover it with grout. The waterfall will be connected to the background. Now, my question: Should the background go all of the way to the bottom of the tank? Or just to where the false bottom starts? Since it's going to be grout, it will be pretty heavy compared to great stuff, so if it started at the bottom that would mean that the waterfall would have to go all of the way to the bottom as well, because the top of the waterfall will be about 7x7x24 cube that's in the corner of the tank, and the stream running down into the water will be integrated into the background and cut across the substrate and finally into the water. I hope I explained it clearly enough because I'm having trouble understanding what I just typed myself... I'll repeat the question so you don't have to take the time to look for it; should the cube part of the waterfall that I mentioned go all of the way to the bottom glass of the tank? Or should it only go to the top of the false bottom where the substrate begins? Because I'm guessing the 'cube' will be pretty heavy.