Mine use todo that. It grows really fast like that. So fast, it's hard to maintain. I guess I'm lazy and really saw no change in chemistry once it stopped turning. But that is a cool video. Thanks for posting.
And it's funny you would post that because I was just reading that that is the way chaeto likes to be kept. When I did it it was just to keep stuff off the bottom. Then one day it started spinning like a wheel.