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I've been through many air pumps over the years, and this model is by far the quietest. This is my second unit - they don't last forever - all air pumps drop in performance over time. The key is the choice of airstone to pair with it. With the right airstone you can get away with a much lower volume pump.
When used with a (under $5) 40mm hydroponics air stone bubble disc aerator, you can get an impressive column of tiny bubbles. Avoid the standard aquarium air stones and tubes as they tend to produce larger bubbles that don't absorb into the water as well.