Two AC110 and an FX5?... you're overkilling it.
Keeping in mind you are going to keep the two AC 110 running then the right call would be the CF500. With a CF500 you'll get a lot of flow, a lot of mechanical media and a very decent amount of biofiltration. 2 AC110 and one CF500 are delivering the so hyped 10X flow rate to youir tank, so there's not need to invest on a very expensive FX5.
Keeping in mind you are going to keep the two AC 110 running then the right call would be the CF500. With a CF500 you'll get a lot of flow, a lot of mechanical media and a very decent amount of biofiltration. 2 AC110 and one CF500 are delivering the so hyped 10X flow rate to youir tank, so there's not need to invest on a very expensive FX5.
