Every tank is different. I have a Tunze 9002, but it requires an exact water level to work right. It does a great job skimming though with a ATO. I highly recommend you get a Avast ATO. It is very important to have on any salt water set up. If I was going to use a hang on the back skimmer I would look at the Remora. I think Reef Octopus has a nice type also, but not sure if skimmer rating is for larger tanks. I have heard good things about the aqualife skimmer, but it cant be nearly as good as the tunze or remore. I also think Hydor has a new nano skimmer that is worth looking into.