One unit...
On this page there is a VIDEO link at the top, as well as pics of the tank.
http://archiv.korallenriff.de/28interzoo/Tunze_04.html
Youtube also have a few vids, like a 75g with a 3" wave...
http://www.youtube.com/watch?v=QuVL6nYEqmc
Your stand and tank better be sturdy though, as you can see, its some massive weight shifting going on! It almost scares me... thats the only reason I dont have one.