What is the most quiet return pump?

[neoh]

speedwave's are really quiet - like, really.. really quiet. But make sure you have a backup, as mine (as well as a lot of others) die within 6 months.

The Tunze silence is what I replaced it with, and it's quiet - but not as quiet, as the speedwave. Out of all I've used, those two are the quietest.

[Magickiwi]

I have a QuietOne 3000 and it runs perfectly silent unless it's touching a wall in my sump. The Eheim pumps I have definitely run a little more noisy but still close to silent.