The lack of damage at 7 inches to a light is because of all the convection have going on, with lots of good wind being made. This is a good method. It's like using two buckets in hydro, one inside the other with airlines pumping O2 to the root zone. Only difference is you have soil holding water and nutes, and don't cycle you water around at all. Don't need to. Puts oxygen in the water, gets taken up by dry soil as needed. You could go away for a few days and things would be fine.