there loud at the beging but if you take the tube out from the thing inside, or put the tube under water there quite,mr saltys sooo right, the skimmer is well i wont go there lol, but anyways its a good mechanical filter and i like the fact that theres 2 cartrages so if you want to change one to keep up the biological filteration(if none is in the rest of the tank) you still have in the other cartrage