Eh, you expect useful details from these people? You are a very, very nice guy. Bottom line is - most of Knotts tanks have serious filtration - especially mechanical. But not all. I believe that it is all in how
everything is maintained, not in what piece of equipment is used or what fertilizer is being added or not added.
For years ADG in Houston, Texas (http://www.aquariumdesigngroup.com
) ran planted tanks for very generous clients in a very straighforward way - their own mix of rich substrate capped with inert gravel, CO2, and always the same type of lights. Zero water column fertilization. Pretty puny canister filters and very bad flow rate and flow pattern. Zero testing of parameters. Their tanks stayed clean - with extremely high paying clients you got to be the best and ADG were and will always be. Houston is a huge town and you can not afford to visit every tank every other day. How did they keep all these tanks clean I do not know but it is all in how it is done, not about equipment, parameters, and ferts. After they paired up with Amano they started using his system but often it was obvious they also did whatever is practical. These days they are about to come up with their own line of everything planted tank and we will all see the same thing - whatever is popular in the internet as a way to run a planted tank is not what they do and advise. Including some of ADA's approaches/products.
Amano has a single published diagram of the sump at his house. It is full of bioballs from all things. I do not recall seeing mechanical filtration. But keep in mind - this entire "big tank surrounded by a pond I designed outside" is part of the marketing. Naturally there is a lot of interest how the big tank works. Naturally we will not know the whole story. A nice, simple, clean Japanese diagram is what we get.