I would go with the 550's. The tank isn't that long and the 550's in my opinion should do the job. If you get the hydor controller you can get adjhustable powerheads so you can dial in the gph
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.