What size pump should I buy for a pondless waterfall.

Measure the waterfall weir, which is the width of the water across the top of the fall. Round up to the nearest foot.

2

Measure the height of the waterfall from the weir to the surface of the water where the fall hits. This is called the head. The head is the amount of mechanical or gravitational resistance the pump will have to overcome. If you have 90-degree angles in your tubing, add 1 foot of head for every one to two turns. Add 1 foot of head for every four fittings or adapters in the tubing. Add 1 foot of head for every 10 feet of tubing between the pump and the fall after the initial 10 feet.

3

Multiply the length of the weir by 1,500 gph for a medium flow -- about a 1/2-inch curtain. Use 1,000 gph for a lighter flow or 2,000 gph for a heavier flow. Look for a pump that will move the correct number of gallons at your waterfall's head height. For example, a 3-foot weir requires a 4,500-gph pump. If the pump is rated in gallons per minute, divide the gph by 60. A 4,500-gph pump is equivalent to a 75-gpm pump. If the waterfall is 5 feet high with 20 feet of tubing and three turns, get a pump rated for 4,500 gph at 8 feet of head.

Thank you