Affiliate Links to the Products Discussed:
Vibration Pads for equipment out of the water (https://amzn.to/2HKMDnu)
OXO silicone dryer mat for equipment under the water (https://amzn.to/2TFadnX)
Silicone Tubing to isolate pump vibration from pipes (https://amzn.to/3emIrWH)
Skimmer intake silencer (https://amzn.to/3oOXoFJ)
Hanging shelf for external pump to isolate vibration (https://amzn.to/2TPeHbn)
Sound Panels:
Sound absorbing panels in the room (https://amzn.to/386LPnH)
DIY Sound Panel Parts:
Owens Corning 703 (https://amzn.to/2UoxAlL)
Roxul Safe & Sound (https://amzn.to/3ndMyHH)
Guilford of Maine Fabric (https://amzn.to/35jcE6e)

Continued:

Keeping the Reef Aquarium Quiet