Well, that's what I was wondering when I bought a Jebao DCT4000 pump. Some said it would quiet down within a few days. Nope. Never happened. Moved it out of the DT out into the garage for use on my mixing station. Lots of power, but the loud whiney noise, at all power levels, was a huge disappointment. Zero customer service when I enquired about the issue. So now I use a Reef Octopus varios2 and it is plenty powerful and completely quiet and they have great customer service. Triple the price though.