I realize this is an old thread.
However, wouldn't cycling a 1/2 HP waterfall pump 1 minute for every 5 minutes be pretty in-efficient? Not to mention hard on the pump unless it is designed for such cycles?
Sorry I know more about ponds, waterfalls, fish and filters than I do about the electronics. I know it depends on the pump as to if it can handle continuous duty or if it wants short cycles. However, a pond waterfall and filter are not going to be very effective for the pond filtering and aeration if the pump only runs in such short bursts.
What is the purpose?