Assuming you're planning on putting a few propeller pumps in the main display for flow/circulation, you really don't need all that much going through the return pump. So a Sicce 2.0 should be enough. Keep in mind, however, that you're only going to get about 250 - 300 gph out of the pump because of the back pressure on it.
You might consider the possibility of putting a separate Sicce Synchra 0.5 to drive your media reactors. It's a heck of a lot more convenient to have a separate pump for your reactors, since you don't need to turn off or valve off the main pump to service the reactors.
If you don't already have the BRS reactors, I would recommend the two little fishies phosban reactors instead. The take up less room in your sump, have a lot more convenient setup for holding the media, and are a heck of a lot easier to open up to clean/replace the contents.