I still own mine without box... The noise can be quieted with free mod using the top of plastic container. You line the edges using air tubing and wedge it into the side that doesn't lead to the cup. What a difference! People that have stopped by have asked why mine is so quiet without me mentioning it.
I had it on a 56g and did great. I didn't get the box cause of unstable water height. Easiest, best skimmer I have used thus far.