very impressive build..
I really liked how you built that back wall on the stand to keep noise in. I hava a 90g as well and the return pump is silent, the overflow is silent, but the water coming down to the sump makes noise even with a filter sock so that back wood wall is a great idea.
Another great benifit to the BEAN system is that it is made to be silent... I submerged the pipes under water to reduce noise at normal functioning level and so far the only thing that is really loud is the return pump although it is like new it is quite nosiey and is the first thing on my list to get replaced.