Thanks for the link that thread is a good read. I think I may be misunderstanding what you mean by humus as to include a humate fraction and a fulvate fraction, as my original contention was that humus is so thoroughly processed that it does little but provide a good bed for the organic processes to continue.
In your research have you come across any plants that grow full submersed and have a nitrogen fixing capacity? It seems like a system like this would need to draw more nitrogen in through N2 fixing in order to be able to replace the nitrogen lost to a completed cycle. Or do you intend to incorporate an aquaponic portion using legumes or some other nitrogen fixing plant?
That I know of, there is no such aquatic plant that can do that. If there is, I'd be happy just to possess it.
The humus itself is a mere a sink for nutrients and is to host the very biological activity I'm describing and thus promote. I also comes with a few nutrients, though not many, can serve as an alternate, bio-available carbon source and triggers favorable hormonal responses from plants.
The same activity that will eventually create P and N. This ought to be easy after a tank is established in this fashion given the fact that it is a closed system and we do tend to overfeed and not vacuum our substrates hence my insistence on a capping material with a very high CEC. You hold N and P in the substrate from food and poop and the necessary bacterial activity will release it into a useful form provided you can meet or exceed chemical oxygen demand. This can be tricky.
There is wisdom in this. If you can PM me a reminder for tonight, I will share some of my source material where wetlands were studied and this material reveals, incredibly enough, that high P and N are actually lethal to wetlands, encouraging the production of some very caustic substances that are also anti-microbial as well as, surprise surprise, trigger massive algae blooms that do throw such habitats into tailspins.
On average, the typical bog receives less than 1 gram per square meter per year of N or P ,astonishingly enough, which is enough to replenish what is in reserve in the soil of the bog. Remember, the plants in that bog are getting what they need from the biological activity in their natural substrate is providing it almost on demand as it reduces all the poop, dead bodies, leaves, etc, which happens constantly, such that adding more throws the system into chaos. A bog is, after all, an organic soup so throwing that little extra in there is a bad thing.
This is what I intend to replicate. A completely biological solution that does not force us to essentially have our tanks teeter tottering on the brink of eutrophication or starvation. This is where I seek to find the balance. Ultimately, the system will be self feeding as long as you feed your fish and do a water change every now and again.
Almost naive the sentiment but I feel strongly that replicating the wetland ecosystem is the way to go and that means establishing several elemental cycles like iron and sulfur and the accompanying microorganisms. Granted, getting enough P and N in for the initial start up is still proving tricky but that's why it's a public discussion. Many minds are better than just one.