How To Size A Garden Pond Pump To Your Needs
A garden pond pump is used to circulate or move the water in your pond. It is recommended that you recirculate at least one half of the total volume of water in your pond each hour.
This rule of thumb works well for a pond with only plants; without fish or some sort of feature like a waterfall or a watercourse.
If you have a pond that is 2000 gallons in size then a 1000 gallon per hour pump will work just fine to keep the water quality just right.
Pond pumps come in various flow rates and this should be considered a minimum.
Features that make a great garden pond!
Fish require a larger turn over of water because of the toxic waste that they produce.
You may only start out with 2 or 3 small fish but they grow and you may want a couple more. Then it would be better to turn the water over in the pond each hour. This will ensure a better environment for the fish and much cleaner water to view your fish.
So for a 2000 gallon pond I would need a garden pond pump with a 2000 gallon per hour rating.
Waterfalls have their own requirements because you are trying to achieve a look for your pond.
The wider the waterfall is the more volume of water you will need. Also the higher that you have to pump water the volume or flow will decrease.
A good rule of thumb for a waterfall is for every inch that the waterfall is wide you should have 100 gallons per hour of volume.
So keeping with the 2000 gallon per hour garden pond pump as an example it should be capable of pumping to a height of 2 feet and still have a volume of about 1800 gallons per hour.
That will mean that I could have waterfall of 2 feet high and a spillway of 18 inches wide in a pond of 2000 gallons and also support my fish very well.
This rule of thumb of 100 gallon per hour per inch of spillway should be a minimum requirement for a water fall. If you use flat rocks for a more natural look you can lose water under or around the rock decreasing the desired effect.
One way to combat water loss in your waterfall is to use a product called waterfall foam. This foam is made to seal the gaps between the rocks so they are water tight. With the rocks water tight all of the water will flow over instead of around or under the rocks increasing the effect that you are looking for. This foam when dispensed from the can is black but within a few days it will blend in and will be almost impossible to notice.
Even if the rocks are water tight between them a 100 gallon per hour per inch of spillway is a minimum and you can end up with an undesirable effect for your waterfall. A better effect can be achieved with 150 gallon per hour per inch of spillway rule of thumb.
A watercourse requires a large flow of water and must be constructed properly.
A watercourse differs from a waterfall because with a waterfall the falling water is visible when it goes over the edge of the spillway creating the effect that you are trying to achieve.
But with a watercourse the flow of water must pass around, over, under, or between the rocksthat you place in the watercourse for a natural look. If you plan on using small stones or pebbles in the construction of your watercourse the water will pass around, through, and under the stones making the flow of water invisible to the viewer.