As I'm looking at this photo of my set-up I am realizing that I could have gotten away with shorter lengths of air line. The lights are going to be lowered to within a few inches of the net pots, but harvesting, accessing the inside of the container to check nutrient levels, or maintenance on the air bubblers would have required disconnecting the air lines to raise the lights. I was careful to cut each air line the exact same length so each tub receives the same air level. In this case, I think it's a typical "six of one and half a dozen of another" scenario.
Here's a closer view of the net pots, air lines and storage tubs. I struggled with the decision not to reconfigure the air lines. To avoid the hassle of turning everything around so the air lines would be in the rear of the table and out of the way, which also requires me to move the air pump mount, I decided to wait a couple of weeks to make the changes in conjunction with doing the first water/nutrient change.
Each eight gallons of water in the 10 gallon plastic storage tub has 1 large air stone located in the center of the tub. Hopefully this will help ensure the aeration is consistent throughout the majority of the root zone.
I need to do some additional work on the way this air pump is mounted. The pump has rubber feet to reduce vibration, but since it's mounted under the floor near my upstairs living room area the vibration causes a little more noise that I predicted. I think that will be easily remedied with a minor modification to the mounting method by installing two more hooks so that all four rubber feet are out of contact with the wooden floor joice.
One pump provides air for all four tubs. Here's a close-up of the "bubbling".
This is my first time using hydroton as a growing medium. I wasn't sure it would wick water very well and was prepared to hand water my seedlings for a week or so, but this picture was taken a couple of hours after adding water to the tubs and the hydroton actually wicks very well.