What is it sitting on? Most people will put something soft under it to prevent vibration. A a recent conference I went to, Anthony Calfo recommended suspending pumps to help with pump noise.
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,