Thanks Cathar
The whine of the turbine is about the equivalent of a 80mm fan..that was my first thought for comparison..
The pump does vibrate and the case it is in also vibrates - probably resonantly!!
I have the pump mounted on a 1cm layer of foam with rubber washers - clamped with nuts and bolts. Not sure what I did wrong
I have a set of rubber case feet - maybe that will help?
How is your pump mounted to avoid the resonant vibration?
THANKS again.