I saw a few tanks on Youtube where two tanks are placed together...how does this work?
http://www.youtube.com/watch?v=C2EIO2hX1Hc&feature=fvw
http://www.youtube.com/watch?v=C2EIO2hX1Hc&feature=fvw
Basically takes the concept of a vacuum. You can try it in your house right now. Take one of those plastic take out containers. Fill up Your sink, put the container in open side first. Submerge it fill it up then slowly lift it and the water will stay in the container.