What needs to be considered when sizing a pump for a waterfall is the depth as well as the width desired, to pour down the backyard waterfall garden.
Start by calculating
head pressure.
Important when determining what waterfall pond pump to install.
I personally love the design of the Cal Pump Torpedo, as seen here. The ease of installation and maintainance and the lack of extra head pressure needed with other pumps makes it a reasonable choice.
Always refer to pump flow charts, found on any quality retail site.
The Waterfall Weir Chart will help you determine what size waterfall pond pump will work best on your backyard waterfall.
3/16"Deep@ 6-11"Wide= 360 GPH,
5/16"deep@ 6-11"wide= 600GPH,
3/8"deep@ 6-11" wide= 900GPH,
9/16"deep@ 6-11"wide= 1680GPH,
3/4"deep@ 6-11"wide =2400GPH,
1"deep@6-11"wide= 3300GPH,
1.25" = 4500GPH
Waterfall/pond pump efficiency and warranties are important when buying a pump. Stainless or metal motor casings usually indicates higher quality and durability. If you spend the money upfront, these pond pumps for the backyard waterfall will pay for themselves many times over.