Rio is a poor choice in pumps. Take it back if you haven't used it much yet. It is a decent size, but in my opinion not large enough for acropora. Go with the other suggestions here and get a mag 7 or 9, they will pump water much better than the Rio and they won't short out and cause a mushroom cloud over your tank. If you must kill your tank with the rio, get a grounding probe to buy you enough time, when it does start shorting out, to get a new pump. I really like dolphins, but I don't think it would work in the application you want it for.