Hint: It's the same thing that was used in the Biosphere II project.
I was going to bring this homemade contraption to the convention for a demonstration but didn't make it.
I hope to do an article on how to build it, and how it can be something a pondmeister can definitely use depending on his or her goals.
BTW I've got all the bugs out. There were some typos in the book Small Scale Aquaculture by Stephen Van Gorder that can throw you for a loop.
