Hi Richard, I have a water vortex in my living space as one of my room decorations. It is part of an aquarium/terrarium/rock garden setup. I've had it operating for over two years and watch it daily. I have never witnessed upward flow in this water vortex. In fact, you just forced me to do what I have refrained from doing for two years. I dropped food coloring into the vortex to watch its behavior. There are two dramatic features, the food coloring produces a well-defined channel around the vortex, and although the food coloring is highly localized in the center, it suddenly disperses evenly throughout the entire water volume.
I'll setup my digital camera and make a video clip of it tomorrow. Dave
