The nutrients are really pollutants, and are what accumulate when you don't do water changes...by export, I think he meant remove them from the system via dilution from water changes.
I have to agree with the person who said a self-sustained aquarium is basically just a poorly maintained planted aquarium. There is no way that it is healthier for the livestock to have a tank without water changes, especially a small tank with a modest amount of water. Sounds like a recipe for cyanobacteria and/or all sorts of pest algae to me. The chances of it degrading into a mess are a lot greater than the chances of it turning into something desirable.