Don't know about the wand you saw used, but it looked like a garden hose hooked straight up to it. At my house, I get 5 GPM out of my water spigot. Don't know what it was like where I worked at, but there was a good bit of volume. How wide was the cylinder at the bottom? Blue wand, I'm thinking was maybe 15-18 inches across, and the slit might have been 1/8"? Not sure how to calculate the flow you'd get from that. Where my math geeks at!?