Disclaimer: I'm a homeowner not a plumber.

How about something like this: Quiet Wrap⢠Pipe Soundproofing Wrap (see link below)

I came upon it when searching for noise abatement of a HVAC duct which started last winter when a new more powerful solenoid was installed for our whole house humidifier. It causes the Aprilaire to suck quick and tightly to the furnace return, sending off pressure waves etc on the vent ducts. I haven't tried the noise reducer yet, but sure enough, with the heat and humidifier back this weak on the specific HVAC duct noise is audible and I believe traceable. None of the HVAC men seem to want to replace the offending copper solenoid, nor check part number on the Aprilaire humidifier. I think it's just too much of a load so I'll probably call them.

Read up on flammability and check with local code department for your booster pump though if you consider using this tape. I'm not familiar with booster pumps (hot water delivery related)?

Good luck.

Here is a link that might be useful: Sound proofing wrap

"The outlet of the pump has a braided 1" line that connects to the house and the connection to the supply is solid."

These are called vibration eliminators. Commonly used in refrigeration systems. Add one to your bypass loop.

What kind of circulator do you have? The small, wet rotor seem to make a lot of high frequency noise. The B&G circulators with a 1/6 hp motor, are much more quiet - then again they're a lot more money.

Here is a link that might be useful: B&G Circulator

I'm using this booster pump,

http://www.daveyusa.com/daveyusa/productsCatDetails.htn?id=3

I'd switch it out but I'm not sure how to integrate the pump you linked to....

It looks like you have a very unique pump & pressure tank.

Does the pump whine? If not, then you need not consider a different pump.

As I said, you could purchase a vibration eliminator, and insert it into the bypass loop.