Is it just mine thats louder then Graham Nortons wardrobe? I was expecting a bit of noise to start with as air makes it way out but im very surprised its continued to make the same humming/vibrating noise hours after?
I found with mine that sometimes the impeller doesn't sit quite right in it's housing. Sometimes just switching it off then on will fix it, or if not switch off, take it apart and make sure the impeller is properly positioned and try it again.
Ill see if i can crack the thing open tomorrow, its a shame because all in all im happy with it makes as a good power head to remove dead spots and the venturi feature is awesome.