Reefoctopus classic 202-s is loud

Seems I am having a similar problem as others, my 202-s is loud. It's sitting in 8in of water, nothing is under it and the rubber legs are touching the acrylic of the sump, no vibration. One of the air vents on the silencer is capped and there are no foreign materials or buildup on the venturi. I connected a 12'' hose to the other spout of the silencer and placed it behind my stand and that helped somewhat. when I cover the silencer hole with my finger that makes the sound almost disappears and of course the water level in the skimmer rises. The skimmer is skimming great besides the noise.