Unless they reveal exactly what biodegradable polymer(s) they're using, I would probably stay away from this. It could be any number of things, and I doubt that they synthesized their own proprietary polymer. Chances are that they are using something that is somewhat readily available that degrades into either carbohydrates or some other bioavailable carbon species. The problem is that it could also have degradation products that you would not particularly want in your aquarium. Who knows if they won't say what it is?