Do you place a plastic bag inside the box, then fill the bag with water? The reason I ask is, I did that today with a cereal box. I put a plastic shopping bag in it, filled it with water and then became a cereal killer. It was an impressive geyser when that 300 grain XTP hit the box at 50 yards, DEAD CENTER. Actually if I was not such a big chicken, I would put my camera down there and just let it run and see if I could catch all that. You must have a remote on and off on your camera or else you burn off a lot of footage to get them geyser pictures on video.