From the owner's manual:
Microbubbles and Noise
It is normal for the Remora to release microbubbles back to the tank, especially during the first week or two of operation. During this break-in period, the skimmer will also run louder than normal. You should see a decrease in microbubbles and noise after several days of operation.
I think "several days" is a bit optimistic, as skimmers can take up to a month to properly break in, but you should notice a reduction once it does..... just keep in mind that between the pump running, the air sucking, and the natural noise of a skimmer, it's not going to become whisper quiet.....