I also agree woth Chaeto, it wont turn and go sexual like Culerpa does. No need to trim constantly prune it, just pull out a certain amount once the fuge gets full of it and sell it.
The shaving brush plant is also a good choice, as well as Mangroves.
Snails to help stir up the sandbed wont hurt at all. I would only do 5 or 6 dpending on the size of the fuge.