[Amazon_Replica]

I made one and it worked fine, then recieved a reactor as a gift. It was pretty simple. A clear pvc tube witha cap on it, in teh cap i drilled a hole large enough for a small powerhead to sit on top, pulling water from the top of the tube. I drilled a bunch of little holes, approx 1/16" all around the bottom sides of the tube. I put a cap on the bottom and drilled a small hole for the co2 line. put a decent sponge in the middle. The co2 comes in from the bottom, the powerhead pulls water to the top and causes a swirling motion, and the bubbles get caught at teh sponge and dissolve as they rise thru it.

A Pretty crude photo