For the ADA solar RGB They hang around 6-7 inches off the rim. Some folks took some readings, based on what I can eyeball, its definitely higher than 80 PAR at substrate for a single unit over a 90p tank.
The lights look a little higher in the photos on your website in most of the tanks but scale can be deceiving I guess.
I am stumped, if they are running 80+ par and lean ferts, the amazonia must be a huge difference maker.
I have Tropica Aquasoil and I can't run my light at 80+ par at the substrate the hardscape would be at 120 - 200 in places and it will get algae easily with only a carpet and small stem plant mass tank.
I did notice some Iwagumi scapes where the rocks are really green at the ADA tank.
High Light + Lean Dosing(+aquasoil) = Slow Growth (and not too much Algae)?
I didn't think this was possible, but if you get as much N and P from the aquasoil as needed and just dose K and a little Fe.
That is how they do it?
I'd love to get to a state where this is possible, I just bought the Twinstar 600s so I have the power to do it, but to stay algae free I suspect would require a whole new rescape and change in understanding of how to prevent algae.
For that particular tank with wood, I'm using a single BML XB, a few inches off the rim - so light levels are pretty high as well.
I think whether flow is an issue or not does depend on what plants you are using in what spot. Deadspots work fine for plants that don't need much flow to grow. Detritus build-up is an issue, but that can be handled with light vacuuming at each water change. I used a single Ehiem ecco pro 300 on the tank - so it had barely 4x turnover (yikes)....
Frankly, I think growing low requirement plants at slow speed allowed me to get away with slow flow, etc.
It would seem if the setup is done well, you can break all the rules, high light, lean dosing, limited water changes and maintenance and still low growth and little algae. I'd love to learn more how to setup a tank to succeed in that way.