Pharma
I think it bubbles the water up the tube, at least that is what it looks and sounds like. The air pump is Y-ed in at the bottom to the water tube that goes to the ring under the water level.

What I have done is run both the drip and the air stones. The pump that comes with it is pretty strong is should be good to run 8 drips. Right now I use it to just run 2 buckets with drip and each with a stone. The roots are huge and almost filled half my buckets once I got to flower after only 5 weeks of veg after planting clones. I am considering going to larger buckets as my roots seem to have filled the bucketes now, I plan on using the drip ring becuase my system seems to be working pretty good though I have yet to harvest. Flowering stage is looking good now.

First pic is after 5 week flower and adding air stones for only 3 weeks of that time.

Last two pics are from last week which is about 45 days flower. They are a little short but they started in a cabinet and were removed to a closet when I switched the cycle.