yeah, you're probably thinking of the right one.
i had wanted to plumb it into the 10 gallon tank i just bought and have it still be the display tank but with nothing except lighting near it.
if nothing else, I might drill the 10 gallon and turn the 3 gallon into an overly fancy looking sump. this will have to do with whether i can procure a 20'ish inch light suitable for the 10 gallon.