Your pond pump is one of the most important elements of your pond. Not only does it provide oxygen to your fish, it circulates water throughout the system, aiding in filtration. The aesthetically pleasing sound of running water is a great aspect as well.
With all the responsibilities of a pump, proper pump sizing is important. It can be the difference between water flowing over your waterfall or barely trickling over it. Likewise, an oversized pump in a fountain can cause water to spew out of the fountain and onto the floor. Incorrectly sized pumps also can lead to premature pump failure and efficiency issues. So take some time to determine which pump best suites your needs.
There are several important factors to consider during your pump selection process:
Pond Volume
In other words, how many gallons of water are in your pond? Gallons are figured by multiplying the average length (ft) x average width (Ft) x average depth (ft) x 7.5. There are differing opinions pertaining to recirculation values, but a good rule of thumb is to recirculate the entire volume of water once an hour. So, if you have a 5,000 gallon pond, then a 5,000 GPH pump is recommended.
Total Head
Total head refers the combined friction losses sustained throughout the piping due to:
• Friction Head- is the resistance to flow within all the components, such as piping, elbows, valves, etc. For example, Aquascape recommends for most average sized ponds, to add 1’ of head for every 10’ length of hose from your pump to your falls. So, if you have 20’ of hose, assume 2’ of friction head. Always verify with the specific pump manufacturer for their specifics. For larger ponds and waterfall streams, a more detailed look into total head should be examined.
• Static Head- Vertical distance from the lowest water surface to highest discharge point.
To use our Head Pressure calculator, click here.
After you have calculated your total head (Friction Head + Static Head), it can be compared against pump performance charts, like the one shown below. These charts give pertinent information, including: maximum head height, flow rates at difference heights and other specifics to help aide in your decision. For example, Aquascape’s Tsurumi PL Series Pump Performance information is shown below for each model.
Waterfall Weir Size
Waterfall weir size is yet another important factor in the pump selection process. It refers to how wide the spillway for the waterfall is. Aquascape recommends 1,000-3,000 GPH per foot of spillway width for residential ponds. For example, if your waterfall weir or spillway width is 2 feet wide, then a pump between 2,000-6,000 GPH should be ideal.
