[Nordic]

But with regards to watercooling and pumps, there is absolutely no problem with having an aquarium pump inside your computer. They are shielded to begin with (all EHEIMs are), and so are hard drives. An immense magnetic field is required to erase even a floppy disk and my engineering friend assures me that I have nothing to worry about. He said something about the non-existance of a device that could completely wipe a modern hard-drive, that sounds wicked!

As a test I put my pump in front of my monitor and noticed only slight discoloration when the pump housing was a couple of centimeters from the glass, even the smallest loudspeaker has a stronger field than that.