Looks fantastic.
One suggestion though, Lower the tops of the durosos so that they aren't higher than the water line in the tank itself. That way if the drain slows slightly (which it will as it gets fouled by algae and whatnot), the level in the boxs will rise then cover the cap blocking the air hole. When that happens the drains will begin nosily flushing. This will both alert you to the problem, AND prevent a flood.
If you don't want to shorten the durosos too much, you can replace the "caps" with "plugs" that will sit almost flush on the top of the T fittings.