You'd probably get better results from the chemipure elite than the poly filters. It would be cheaper in the long run to just buy a good carbon and the GFO seperately (that's basically all chemipure elite is). Dr F&S brand GFO is the cheapest GFO I've seen and the one I'm using..
http://www.drsfostersmith.com/produc...3&pcatid=13963

And you get MUCH better results using GFO in a reactor instead of a filter bag.