Got a few of these and it shouldnt be making that much noise. They will make a bit of noise if the cany cane shaped hard plastic tube is making contact with the lip of your tank and the skimmer is running though. A little felt or velcro will fix that in short order.
While seaclones dont seem to have a very good rep on most forums I havent had a problem with them yet. On mine I usually have the air valve just about as open as I can get it and it not fall out! You might have to readjust it from time to time though.
HTH's....