I have a 20 holding all my livestock after a move. It is a pain to top off fresh everyday, so I am definitely for the ato idea. I have 2 koralia 1's set at mid level ion the back at either side. Both are pointing upwards toward the surface. I have a couple years under my belt bit this is by far the hardest tank to keep stable. My parameters will be fine, and rhen totally out of wack, but I think alot of that has to do with the move, and changing some things. Cycling is not a big deal, throw a shrimp in there and wait like 2 weeks and test for ammonia etc, and see where you fall. Just move slow. Somebody mentioned a sump, that would be good too. Above all though move slow, slow, slow. There is nothing more defeating than a failed attempt at this hobby, good luck, and happy reefing.