Thank you and thanks for looking! We have the smaller one (1k) in the 32 Biocube and it's dead silent. Maybe you got ahold of a bum unit?Very nice tank reefer! I have the same icecap 3k and it works really well, do not got for the smaller version of the icecap!! I have it and boy does it hum and hum its insane the amount of noise it makes.