Looks like you have a lot of fun with poop! Good stuff, but it wasn't really a full comparison. One test included a back flush, the other didn't. What if you ran the 3" dump followed with a spray nozzle (permanently mounted or the wand type) into the tank? I think that would produce similar results to the back flush. Besides, as you point out in the video, most dump outlets are not a 2' straight pipe from the tank to the valve. Mine runs across the width of the trailer then makes a turn, so the back flush would be worthless. Glad you had fun with it, and it hope you've added a pressure regulator to your water supply!
