ok from what I found out on other forums it is a nano skimmer that is powered by a power head.(after sifting threw Japanese translated to English pages...lol)
I would hook up a power head to the L shaped tube and see what happens. I think there is a impeller in the skimmer that makes its own bubbles once you supply the water flow By creating a vacum in the center housing were the water goes in.The little inltes sticking out is were the air gets sucked in. hope this makes sense. | 
