Thanks for the comments and the welcome, all. have already disconnected the
filter and noticed no appreciable increase in flow. And the pump is already
grossly oversized for the filter I am using (at least according to the
Pondmaster data). Thus, I will try and increase the size of my tubing next.
If that doesn't work, perhaps I'll supplement with a second pump or
waterfall pump.

One question still, though:

Even after I bump up the size of the equipment, the flow may not be the
"raging torrent" my wife is looking for. What do you guys think about the
Pondmaster waterfall pumps? I have used the mag pump because they are darn
near impossible to kill -- even running dry. I use them on my indoor
aquariums, too. Are the waterfall pumps by pondmaster as indestrutible?
Even if not, are they better than the competition in the direct-driven
waterfall pump class? I continue to be interested in them because I can get
them wholesale through a relative.

Thanks,
Scott