I tried it once on a 6100 and i was not sure about the long term stability. I got the impression thet the 6100 was slowy moving up when on, never ran it long enough to see if it was moving so much that it was a concern.
One thing you could do is to file a Notch into the bottom of the clip so it lock onto the bracket or use a cable tie, to lock the clip onto the magnet.
Also you may find that once the ouput hits the glass bottom a large amount of force is lost.
I now have the 6100 mounted normaly but at the botom of the tank blowing across the back this seems to work better then a downward facing stream.
the tank is 6 by 2.5 feet