Slim skim 65 problem

[fscmocsaj]

I just bought a slim skim 65 for my newly established reef tank and contrary to all the reviews mine is a bit loud. Does anyone know why I would have this problem? my air valve is completely open as the instructions state and the collection cup sits about half way with a quarter of it in the water. The water level is in the middle of the top grate.

 

[fscmocsaj]

My out take of my canister filter is right next to the protein skimmer but I don't see how that would affect it.

 

[fscmocsaj]

Anyone? just need suggestions or your input.