Once those three pieces were good and dry so we were sure the seams wouldn't get ruined we flipped the whole thing over onto the last side and finished up the two seams to get all our sides as one piece.
Last we glued the bottom of the tank on and did this seam all at once. I called in my dad to help us on this one because the longer sides would want to bow a little bit and i needed both dad and brother to hold the two sides in place while i went about gluing and checking. Next was to make the top flange on the tank which helps to strengthen the whole thing up and make sure the sides don't bow out over time. Plus its nice to have something to keep it from just being an edge that might get annoying if your arm was leaning up against it while working in the tank. Marc does his flange all in one piece by cutting out the center which really is the better option but our tank was on a budget and we had just enough material. Also, Marc recommends leaving your pieces a little long so that they stick out past the seam a bit and going back and routing them off at the end. (Go to melevsreef.com for clarification) I would suggest doing this if at all possible because it makes gluing much easier and probably improves the overall look of your corners. We did four pieces and glued them together to make a flange and then glue the whole thing onto the tank.
For these seams we had to hang it out over the edge of the table because otherwise the glue goes through and soaks under the pieces leaving you with i big old smear in the flange (which we figured out the hard way) A couple of wood clams do a great job holding the pieces in place while you glue. So after all this we have ... a box.
But more importantly we have a box that holds water!!
Yippiy skippy it doesn't leak.