I had to filter a week in my 240-gallon aquarium in use. He transformed it into a white water system. The gouramis who actually prefer the upper layers of water were to be found only on the ground and fought against the current to. While the noise of the filter is not so much bothered me in the beginning, I hum but went for a week on my nerves. The aquarium is in the living room, and as one might even sometimes be left in peace. I have several methods trying to contain the noise level: foam under the supplied hanger (on the first evening) have brought something. Still too loud. Complete immersion in the aquarium has brought nothing. The attachment of the suspension with suction cups (rubber was supposed to insulate) on the disc made the filter even louder. Hence my conclusion: nothing for living quarters and the aquarium should have more than 300 liters. Of course you can also use the included diffuser. That would somewhat reduce the water movement. The air noise would then be many times louder than the engine noise, although it of course is a beautiful sight with its many small air bubbles. It would be desirable possibility of adjusting the filter performance and a better manual, which has remained totally content because of the many languages on the track. The images in thumbnail size do their part. I have returned the filter after I installed new cartridges and gained me another filter from EHEIM (also here at Amazon). An external filter Professional 3 - 350. Here the manual is better. He's a bit quieter, but also audibly. Whisper quiet is something else. The return of too loud for me powerhouse went without problems. Kudos to Amazon this!