I've decided to do away with the waterfall pump (if possible), and just go with the filter pump. This is an existing system with the filter, and pump I installed last year. The pump is a 5000 gph, sized for the filter (4000 gal pond). I am looking for ideas on what to do with the suction side of the pump which now is the discharge side of the waterfall pump. This is 2" to the waterfall, the suction side of the filter pump is just above the discharge side in the waterfall. I know I will have to put a pup in between the two existing openings in the waterfall, but am not sure about how the velocity of the water will have on the fish. Thanks.