Boyu Glass Diffusor makes tiny bubbles in my tank. It only diffuses through 1 spot of the ceramic disk, but the bubbles are tiny, and I have my co2 where I want it. Stick it under a powerhead, or intake to make the bubbles stay longer in the water. Bad thing is tube falls off the the glass barb sometimes. It looks good, does the job.
Co2 mist, pretty looking
no suction cup, breaks easy, tube falls off the the glass barb