In my experience . . . depending what kind of zoo's they are . . . some grow alot faster than others . . . the surface doesn't really matter I don't think . . . They've been thriving in my tank and I've manage to grow them on acrilics, plugs, ANY LR and even aquarium glass . . . oh and dead corals. . . w/o using and glue whatsover . . . just elastic bands
But as for the growth . . . Like I said certain zoo's grow faster than others but not because of the surface that they're growing on . .