Eheim pumps are inaudible, i.e. silent (even the 1250) if well dampened from the case.
The only noise you can hear is the typical short rattle of mag drive pumps at startup, or when there are remaining air bubbles in the loop passing through the impeller housing.
My 1250 is so silent that even from a few inches I can't hear anything.
Only when I touch the pump I can feel it's running (vibrations).
That's why I installed a digital flowmeter in my loop...
Can't speak for the Iwaki's as I never owned one.
CD
