I'm highly suspicious that it would make any difference at all to the oxygenation; has anyone actually measured it (it would actually be quite easy to measure)? It's a long held misunderstanding that airstones, for example, directly oxygenate the water - they do not. What they do is to promote circulation in the tank to bring stale water to the gas exchange surface. It's surprising to me that this myth still perpetuates. I suppose if one's tank were woefully under circulated scrubbing-bubbles might make a difference, but not in a properly circulated system. I also find it borderline absurd that these bubbles somehow enhance organics removal. This is a much trickier thing to measure, though long term nitrate levels could be a way to do it. Again, in a poorly circulated tank, organics build up might be problematic, but essentially turning your tank into a huge protein skimmer just seems like it would make a massive mess when better circulation would accomplish the same thing. None of this passes the common sense test to me. As the old saying goes, extraordinary claims require extraordinary evidence. I'm still waiting for some of the latter - beyond unreliable personal anecdotes, that is.
