I got one of those timers that use the little green and red pieces you stick in for on and off. My return pump is plugged into the timer.
I don't use any red 'off' pieces though. Just green 'on' pieces spaced about 3 hours apart.
When I feed - especially phytoplankton or small stuff like rotifers and sea fan food - I simply manually roll the timer over to 'off' and automatically within 3 hours it comes back on.
Otherwise I'd be prone to forgetting.