Top of the holes in the net.put rocks in while it's bubbling.fill rocks till bubbles are right under them.set peat pellet over the rocks so the tap root coming out the bottom can sink into oxygenated water nutrient solution.water is chilled and full of beneficial bacteria.why would I want my roots in the air.if I did I would scrap DWC and go aero.
I use to do it all other ways but the air gap between water and the rocks was a breeding ground for algae and larvae.warm air from outside and all that moisture around the rocks and net was bad news.
Now I have 0 algae issues and no more drain fly larvae.
I want all my roots submerged up to the crown.