I have a 300 gallon stock tank that will flow into a 150 gallon tank than into a 20 foot stream. At the end of the stream, there is a 9 inch drain with 3 inch piping out from the drain that I need to route about 30 back up to the 300 gallon stock tank. I have two ducks who will enjoy the larger stock tank. Do I need a 2 waterfall pumps or spillways PLUS a large pump to recirculate the water back up? Do I also need a holding tank? I can't get a straight answer so any help would be appreciated.