What pump should I use for a waterfall?
To choose the proper pump for a waterfall, you first need to understand pump head height. This is the water pressure generated by a pump. The maximum pumping height is the height a pump will raise water straight up resulting in zero gph of water flow at the top. As the height of any pump discharge increases, the flow will decrease. For example, a 1000 gph pump may pump 850 gph at a height of two feet, but only 500 gph at a height of ten feet. To calculate the pump size for your waterfall, decide the width of the spillover you want and determine the vertical distance from the top of the waterfall to the pond surface. Every inch of spillover width requires between 100-200 gph of water flow at the height of the waterfall. For example, if you want an eight-inch wide stream over a waterfall that is four feet above the pond, you need a pump with a flow rate of at least 800 gph at a height of four feet. Again, when in doubt always purchase a slightly more powerful pump. You can always slow or divert the flow of a pump, but you can't increase it.
For a light flow, you can figure 50 gph times the width of your waterfall (in inches), 100 gph for a average flow and 200+ gph for a strong flow.
Waterfall products and informational videos can be found on our Pond Blog.