Just to bump this thread up a few years. I'm looking at building one of these myself, and found it easier to understand a diagram rather than photos of a build process I've been looking at.
So I've edited the pictures according your posted specs - note the air stone is inside a tube. Is either of these correct? or does the bottom end need to be completely sealed up, so no holes are drilled.
Should the tube with the air stone inside be sealed either end?
and my main question, WILL IT WORK?
HALP.