I have about 3 Mags, too. I use an old Penguin 1140 powerhead with PVC plumbing to a hose end barb, and drop the contraption into a bucket. Does the same thing as rbishop's setup, except it does not return the water, since I do water changes while vacuuming.
rbishop's setup is more versatile, as he can return water to the tank if a change is not warranted, plus his will pull a bit more suction.
v/r, N-A