powered by an aquarium air pump
You show your Gurgle Garden being powered by an aquarium air pump. The air line terminates into a "T" valve with one side going to the plant, and the other open to the nutrient solution.
Isn't the intention to get nutrient solution to the plant in the upper container? I've got to be missing something because I don't see how you'd get solution up the pipe -- it seems to me that the end result would be a lot of air in the nutrient, and less air going up the pipe to the plant.
Can you please enlighten me?
Don't worry about how it works from looking at the drawings. Just build it and be amazed that it does.
Ask a physics teacher and maybe he can explain the principles of hydraulics or gravity or what ever makes it work.
I work on the principle of trial and error. I keep trying till I get all the errors out.