Choosing the Correct Pond Pump
Pump Terminology
GPH stands for Gallons Per Hour. This rating represents the water circulation that the pump can provide. Please note that pumps have different GPH ratings for different heights. The GPH generally decreases with the height that the water has to be pumped. Pump charts usually provide GPH ratings for specific heights.
Head (lift) is the maximum vertical distance that the pump can force in the vertical line, without tubing being connected. Please note that connecting tubing will generate resistance that will reduce the head. Furthermore, running tubing in a horizontal distance will restrict the head proportionally: 10 feet of horizontal distance is approximately equal to 1 foot of vertical lift (head).
Wattage measures the power of a pump. The cost of operating a pump with a specific wattage can be measured as follows:
Total monthly cost of operating a pump = cost per kilowatt hour * 30 days in a month* 24 hours in a day * pump wattage / 1000
More About Pumps
Pumps are crucial for water gardens and pond because they:
- Circulate the water to prevent mosquito larvae from accumulating
- Power waterfalls, streams, fountains, and spitters
- Pump water through pond filters
- Can aerate the water for fish
You must choose the correct type and size of pump in order to adequately accomplish your goals.
Do you have a statue or a spitter? Then you probably are looking for a statuary pump.
Do you have a large waterfall? Then you probably need a high-capacity waterfall pump.
Is your pond between 100 to 500 gallons? Then you probably need a multi-purpose pump, like the SuperFlo series.
Do you have fish? Then you might want to consider an aeration pump, like the UltraFlo series.
Sizing a Pump
Generally speaking, to keep away the mosquitos and properly turn the water, a properly sized pump needs to circulate the pond water once every 2 hours. If you calculate the volume of your pond in gallons (check out GardenSuperMart's Pond Calculator to see how to easily calculate your gallonage), this means that you will need a pond with a GPH rating (at ground level) of at least HALF of your pond volume.
However, if you have a waterfall, you will need a stronger pump. As a pump pushes water higher in the vertical direction, gravity creates increased resistance. Manufacturers usually list how many GPH a pump provides at 1 foot of lift and at other heights.
Step 1- Calculate the lift height
The lift height you should use is the height from the level of the pump (e.g. at the bottom of the pond) to the top of the waterfall, PLUS an adjustment factor for the horizontal resistance created by tubing. The resistance created by forcing water to flow sideways 10 feet is roughly equivalent to a 1 foot lift. Therefore, you will have to add an additional foot of lift for every 10’ of tubing that is run.
Step 2- Calculate the GPH required
Use a pond calculator to determine the volume (in gallons) of your pond.
To calculate the water circulation requirements, divide this number by 2. Multiply this number by 2 you have fish. If you have a waterfall, then you will need to add an extra 100 GPH for each inch of width of your waterfall.
Step 3- Find a suitable pump.
Find a pump which has the desired GPH at the lift height that was calculated.
EXAMPLE:
“I have a pond that is 5’ x 5’ x 2’, with a 3’ waterfall which is 12” wide, and there is 10’ of tubing from the pump to the waterfall. I do not intend to raise fish in this pond.”
The volume of pond (according to our pond calculator) is 374 gallons.
Lift height = 2’ (from bottom of pond to surface) + 3’ (waterfall) + 1’ (for 10’ of horizontal tubing) = 6’
GPH required = [ 374 gallons / 2 ] + [ 100 GPH * 10”] = 1,187 GPH
Therefore, we will need a pump that will generate 1,187 GPH of water circulation at 8’ of height. The SuperFlo 6,000 might be a good candidate because it generates 1140 GPH at 6’ of height.
Tips
- The smaller the diameter of your tubing, the more it will restrict the flow of your pump. For waterfall pumps, we recommend using 1.5" diameter tubing.
- All barb fittings along your line will restrict the flow of water. To ensure maximum water flow, cut all barbed fittings down to the appropriate diameter to fit your tubing.
- SuperFlo pumps come with flow adjustment knobs to reduce your flow. However, MaxFlo pumps do NOT come with this feature. Restricting the flow of a MaxFlo pump will create back-pressure to the pump, which will blow out the motor. The proper way to reduce the flow coming from a MaxFlo pump is to run more tubing.
