Mark, did you use any aeration during the growth? How does it...

No: for simplicity and ease of scaling, we did not use or try aeration. The boxes we use measure about 13 cm x 9 cm (LxW) and we add 160 ml of solution to each. That gives a decent surface area:volume ratio, or so it would seem. The solution, when changed every three days or so, either contains sufficient oxygen, or there is enough gas exchange through the other holes in the boxes. I have not formally compared growth rates with those of plants grown on soil or in other hydroponics systems, but they *seem* to grow pretty normally, flower, set seed etc. Probably aeration would help but it does complicate the set up. A maximum of six plants per pot is tolerable, though I prefer to use four to give them a bit more space. Depends in part on how valuable your media/compounds are.