I guess the pump itself is not too loud, its more the gurgling/bubling water going back into the tank. The bubble diffuser is overflowing right now and pumping alot of the water over the sides of the box into the tank. Perhaps this will go down when the skimmer breaks in a little more. I was getting lots of sucking noise from the air intake but I read on Reef central to add more airline to the intake and when I did that it almost cut out the sucking almost all together. The problem I had then was when I turned off the skimmer to empty the cup this moring water starting draining out of that airline.. I have now since routher that tubing so it hangs back over the tank so it can just drain back in if needed. I think I need to run a little airline from the output backflow port towards the tank as well as that overflowed a little bit yesterday. I like to try keep my water in my tank rather than all over the floor
Greg