yes. ive actuly built two. it took me seven trys but i did it, and i built it out of compleatly random parts(a gravle vacum, a medicen container, a 20 ounce soada bottle, and some pvc
pipe) i found that the only way to make it was to put it right in the tank. so i got some clear plastic pipe, and i wedged an airstone in the bottom with the airline tubbing comming up the tubing. then i drilled a hole at the side of the tupe near the top that was right above the water level. right above that was an adapter that conected to a peice of 1/2 ince pvc
pipe. i drilled a 1/2 inch hole in the soda bottle cap and clued the pipe to the cap, then screwed the cap the the bottle and presto. the only thing was that the soada bottle was a bit unsightly so instead u could use a smaller bottle.