Remove the sponge and use polyester filter floss instead. This is basically quilt batting. Big Al's sells it. You might be able to get it at Michael's Craft Stores, and you can most certainly get it at Fabricland (I think those are over on the island). Change this regularly.
I use Purigen in all of my tanks, and I've used it in conjunction with GFO. You could place it in the filter basket under the poly.
Having the media basket, you really don't need fluidized reactors for carbon or GFO. The media basket will work just fine for those.
I'm not sure of the chamber configuration on the NC28. Have a look at my contest entry thread (link in signature), and you can see how I squeezed a Hydor Slim Skim Nano into my NC24. It isn't without challenges. I can't comment on the skimmer yet, as there is no water in the tank yet.
I wouldn't do bio-pellets yet. The bio-pellet reactor that would work best for you is an external recirculating bio-pellet reactor. It is made by Reef Dynamics, and it would need to be ordered from the US ($250 + $50 shipping). You would need to T-off your return pump, and carve out the hood to allow the hoses to pass through. If you add a sump to your NC28, then there is another good bio-pellet reactor option, which can be purchased in Canada from J&L Aquatics (the Cad Lights recirculating reactor for $180). Cheaper reactors will work, but the recirculating ones help guard against overdose. If you're handy, there are DIY plans online for modding the TLF reactors to be recirculating.
In the event any parameters do wind up out of line, or anything undesirable happens in your tank, specific recommendations are generally easy to make.
And lastly . . . Tank photos are always appreciated.
