Ampmasters will definitely not work on a timer -- They are efficient because they do not have a strong motor. One of the issues with the Ampmaster is that they don't always spin back up after turning them off.
If you have dolphins the better way to vary their flows is to used motorized ball valves or something like an ocean's motion.
But this requires plumbing and equipment.
In Europe Deltec has a line of Interval pumps which turn on/off is as lil as 3 sec intervals. But these pumps operate at 50hz rather than the US 60 Hz which makes a difference into the longevity of magnetic pumps.
There are some people testing Baldour pumps in the US on an interval system, but its only been for a few weeks so far.