I threw some chaeto in a couple of my 10 gallon grow out tanks. Not sure if it does anything, but it definitely isn't growing as fast as it does in my DT sump. I can tell you though, that it ends up falling apart which becomes a PITA when I vacuum the tanks, I use a rigid tube connected to airline hose, and the chaeto pieces get stuck in the tube.
Some of the fry sleep in it, and I worry that they may get stuck (hasn't happened yet).