jet pump noise
 

I have a 3/4 hp jet pump filling a tank and another (the same kind) filling a pressure bladder from the first tank. The one that fills the tank is very very loud but it is pumping fine. I just hooked it up but its not new.

What could be the source of the noise?

air??
 

The most likely source is air (cavitating) it may need to be bled better, or it may have a leak on inlet. But the pumps should sound very different, one is pushing about 40-60 lbs. of pressure, the other has no restriction. Just a thought, good luck......