I have a funnel with a tube leading to the return line in my sump. The output from my carbon reactor empties into the funnel, much like one of the "miniature toilets" that you spit into at the dentist's office.
My automatic feeder is filled with a mix of pellets and freeze dried Cyclopeeze, and dumps into the funnel. The food is then pumped to the display tank through the return lines.
The nice thing about it is that by the time the pellets hit the display, they're saturated, so they never go into the overflow. You can tell that the feeder has triggered when all of the fish start darting around the display like crazy!