I think I need to learn about the water chemistry and get some equipment to be able to test it. I know zero about this so far.

The diagram is very nice. Easy to understand. I'm not exactly sure of the purpose of the hose barb, or if the same system would work without a hose barb in place?

Is the purpose of the barb to reduce flowing water volume and increase pressure, enhancing the ability of incoming air to be able to mix with water? Or is it to create suction? Or both?