Pump Hum

[Werbo]

Ok. It has been my quest to run an ultra-quiet system. Main reason is that I have a great tenant in my basement suite that is directly under the tank.
I did extensive research by asking for feedback from Canreef members. Thanks to all who replied. I decided on Eheim pumps - one 1262 for the return and upgraded my Euro-Reef RS 180 to the modifed Eheim 1260. These pumps are ultra quiet and I highly recommend them. When you are beside them you can barely hear them other than what I describe as a "white noise" hum. This is no louder than when a new fridge cooling fan kicks in.

Question is. I have noticed that the "white noise" hum is magnified through the walls and floor in both my bathroom behind the tank and downstairs under the tank in the laundry room and basement suite. It is actually quieter in the fish tank room/closet.

I have tried foam under the pumps and there is foam under the sump. It makes no difference.

Any suggestions?