Those are tuff containers......how much water do you put in 1????
None, they only house the roots, after each mist cycle the water returns to the res via pvc plumbing which threads onto the spigot visible on the bottom of the bottom container.
This may help to clarify - the res is pictured in the foreground in one shot (black with feed / chiller lines visible), the feed lines are black and penetrate the container to connect to the manifold on one side. These are all construction pics, didn't have my return lines in place yet, they're 2" PVC.
Sorry for the hijack, just thought it appropriate given the question.