Freankly I'm not too sure just what's in this product. My faith in label laws, such as they are, tells me that it must do something close to what it claims. And yet, I can't see how it would accomplish any of that. To remove something from your water, you need to somehow physically extract it from the bulk water, kinda like activated carbon will adsorb organics and hold them in the filter (until all the adsorption sites are full).
But to just add something to your water? No, impossible. The best I suppose could happen is that it could somehow bind up some organics so that they settle in your substrate. I'm not too sure how one would accompish that, well, without using chemicals that would likely be worse for your tank than fish wastes. But even so, is that a good thing? I don't think so.
As far as NO3 removal, yeah, denitrification is possible, but why? As RTR said, you're just losing your best indicator of pollution.