Microbubbles?

What are microbubbles? and why are they so bad?

 

Microbubbles are tiny air bubbles that are introduced into your water column through a number of different ways. If you are flowing water too turbulently near the return of a pump, there will often be microbubbles. Powerheads, wavemakers, protein skimmers, phosphate reactors, refugiums, carbon reactors, ATO units, etc can all be contributors to microbubbles.

That is what they are.

I will leave it to more experienced reefers as to why specifically they are bad. All I know is that they are bad and that if my sump gets too low and blows microbubbles in the tank, almost all of the corals will not extend completely.

 

I have some bubbles for oxygen production by aiming the powerhead to the top. Its not whole lot of bubbles but still bubbles, are they okay?