High density foam for insulating sump noise?

[Hal]

Does anyone know where I can get a high density foam for putting under my sump (Rubbermaid horse trough). It needs to be able to withstand 600 lbs of weight distributed over a 2x4 ft area without completely crushing.

My return pump and skimmer pump are hard plumbed into my sump, and are causing vibration of the sump against my concrete floor. I'd like to isolate the sump from the concrete to reduce vibration/noise.

I was thinking a foam rubber might do the job, maybe an inch thick?

 

[Avi]

you can get it at an upholsterer.

 

[poppin_fresh]

I would recommend 2" thick pink (or blue) board. You can get it at any home center in 2' x 8' tounge and groove pieces. It is used under and around concrete slabs because of its compressive and insulative strength.