i have reef octopus s 130 and its really loud. i have sound proof foam,rubber pad for vibration and door to competely isolate the sound, But it still bothers me when im sleeping eventhough its few feets away. It was been loud since i got it but it recently got worse. The weird thing is that i run a low nutrient tank so my nitrate and phos is really low but is skimming crazy even with lowest setting. Im not sure this is due to defect pump.