I'm speaking from years ago on this one. I had a 90 gal fish/reef and made the jump to Aqua C Urchin Pro (I think that's what they were calling it then?). I had tried a cheap Aqua Clear that was tempermental and really didn't do a very good job of skimming and constantly needed adjustment.
Like many, I waited for days for the (used) Urchin to break in for me and began to worry. A few days later it was pulling excellent skimmate. Most of the microbubble subsided but there were still some getting back into the tank.
I bought the Aqua C Overflow Filter Box and within hours my tank was crystal clear again. Plus I absolutely liked the fact it broke the water surface for me which was an added benefit.
Long story longer, the 90 gal is long gone and now I'm down to a 36 gal bowfront with a new Aqua C Remora Pro and an MJ1200 pump. The microbubbles are less than the Mag 3 I started with in my 90 at first and then upgraded to a Mag 4 later. I still think I want to break the surface water and still getting a very small fraction of microbubbles I'd like to eliminate altogether so I'll be getting another one soon. The good thing though is I can actually fit the MJ1200 right in the box though which I couldn't do with the huge Mags.
So to answer your original question yes they do work and IMO also make it work a little better.
