[Putawaywet]

If you have them aligned properly I think they are pretty darn quiet. I can hear a slight humming as they ramp up and down but I have to be standing right next to mine.

As for the corner overfllow, I'm not sure if you are running a Durso or similar, but about the only thing a wave would do to increase noise would be from the waterfall effect as it pours into your overflow. If your water level in the overflow is already up near the overflow grating then the increase of noise would be very minimal. If it's not, then you will hear a bit of an increase everytime the wave rolls in. Beacuse I am gravity feeding my skimmer I have a secondary standpipe that keeps my water level in my overlfow as high as my tank so I have zero water fall into my skimmer.

Someone else with a similar sized tank will have to tackle your wave question.

Brett