Morning Steve:
Welcome home from the wars at Koiphen.... If you go to:
http://www.aquabead.com/
you'll see the agitator on the first picture of the filter system, it's the can in the highest position... It's air driven... Aquadyne has same set up but you have to open and close a valve to use and shut down, not really a big deal, but the Aquabead's agitator is mounted on a check valve so all you have to do is turn the switch on and off...A simple but nice feature, especially for old foggies like me who sometimes forget to open or close the valve...
In fact the Aquabead has a lot of simple but nice features to make life easier...
Aloha! Mike