“...now if you need it to be dead silent, unplug the power cords.” -Mario
Lmao.
A while back I bought an Eheim 1250 from a reefer; he said it was very silent.
Later when I needed it running, I plugged it in and sure it was silent, dead silent; it had no impeller.
Another person sold me an impeller for it later. I guess he could remove the impeller of the pumps if he’s not willing to unplug the power.