Originally Posted by Francis Xavier
NPT's use no filtration and no artificial lighting. The problem is, there is no such thing as an infinitely self-sustaining planted aquarium.
Frank, thank you for your journal. I've been following this thread with quite some interest. I'm not sure any one has mentioned it yet, however, but I disagree with this statement.
First, if you look to Walstad as the patron saint of contemporary NPT, she allows for artificial lighting, though that is low and even lower if the tank catches direct sunlight. I believe this is actually in her book.
Second, I think post-publication, Walstad has noted that filtration can be used (the book recommends against filtration outside of the initial set up, but she's softened her stance since it came out I think). Certainly the NPT community either uses filtration through the entire process or at least carbon to help clean up the newly set up tank. Again, her posts on the semi-official NPT forums on APC suggest this shift in methodology.
Third, if you read Walstad's book, she never makes the claim that her NPT method is self sustaining, and I daresay there are no tanks that can make that claim, as you very rightly note. Instead, she advocates that input in the form of food will help see the tank through as plants use up the (admittedly long term) initial nutrients from potting soil.
Finally, while this wasn't Frank's statement, someone commented that NPT tend to be dirty tanks with ugly plants. I've seen some beautiful NPT tanks and unless you're very much in the mindset that iwagumi is the only beautiful tank style, I'd argue that any tank with healthy plants and fish can be charming in its own way - even java moss can be gorgeous with some maintenance. As there isn't a lot of other plants iwagumi, can be aesthetically displeasing as well and for me - who still considers plants secondary to fish - many fish would be happier in an densely planted NPT than in a "barer" iwagumi (anabantoids come to mind immediately).
Anyway, returning to Frank, as a Japanese studies graduate, it appears your approach to methodology approximates the rival schools kind of understanding often present in Japanese arts - especially martial arts and calligraphy (the latter which I know much better).
In any case, I don't post this as an expert on anything; just to point out that your definition of NPT doesn't seem to match what's actually written in the cornerstone text on the matter, nor the forum, nor actual practice. Apologies if I've misunderstood or anything - I just know for the areas in which I consider myself a hobbyist with real knowledge (and aquaria is most certainly not one) I'd like to be called out, because getting better is much better than being right.