Review on Efficient Aeration with Eheim Air Pump 400 by Tiffany Bobcats

Even at full flow the Eheim 400 is the quietest air pump I have ever experienced. Adjusting it down makes it even quieter. I have the Whisper 10, 150, 300, Eheim 400 and the Fusion 700. With 50% less flow the Fusion 700 is equal to or quieter than the Whisper 150 but with less flow. By far the quietest of these is the Eheim 400 (4W), even at full power. Comparing the flow rates on all of them to the manufacturer's specs, I think watts is the best way to compare capacity. Whisper 10 is rated at 1.5W, Whisper 150 is rated at 3.5W. Whisper 300 is 7.5W. If quiet is important, buy 2x or 3x what you need with the adjustable option , and reduce the flow. Eheim is pricey, but worth it if you want near-silence (check out YouTube).