These units produce an extremely small bubble. On average, bubble size is 0.025 mm or smaller which is important for two reasons:
The bubbles are so tiny that their buoyancy is overcome by the surface tension of the water. This means that the bubbles stay resident in the water for up to 10 minutes. A concentration gradient is created, and Brownian movement allows the bubbles to become evenly dispersed in the water, top to bottom. This creates a 100% aerobic environment in the body of water. The oxygen in a large bubble is essentially wasted because they “pop” to the surface.
Lots of small bubbles may contain the same amount of oxygen as one larger bubble, but surface area is greatly increased which leads to much higher oxygen transfer efficiency.
Because of the long residence time of the bubble, the oxygen has ample time to be dissolved in the water.