Before buying a pond pump, there are a number of considerations that need to be made to ensure you choose the size most suited to your pond.
A pump is required to move water in your pond, whether by a waterfall, stream, fountain, or spouting ornament. A submerged pump can be installed into a preformed pond or one lined with a pond liner.
There two types of pumps, external and submersible. For the smaller garden pond, a submersible pump is the most economical.
Pumps designed for garden ponds are sized by gallons per hour (GPH) output at one foot of lift or height. It is recommended that the entire volume of water in a garden pond be pumped per one to two hours. What this means is that a pond holding 500-gallons of water should have at least a 500 Gallon Per Hour pump. When sizing a pump for a pond there are a few other considerations. How high will the pump have to lift water? Will there be a waterfall or fountain? Will there be a pond filter? All of these variables reduce the amount of flow, which could affect water quality and clarity.
Here are useful consideration to take into account when selecting the most appropriate size pump for your pond:
1) Calculate the volume of your pond in litres. To get this value, estimate the surface area of your pond in square metres (square feet) then multiply by the average depth of your pond in metres (feet). This will give the pond volume in cubic metres (cubic feet). This value is then multiplied by 1000 (28.4) to give the approximate pond volume in litres.
2) If you are going to install a filter make sure it is designed for a pond of your size and be guided by the recommended flow rate when choosing size of pump. If the filter is to be positioned above water level check that the pumps performance at the total height above the water level (Head) that the water needs to be raised to. It is worth adding approx 10cm to this height for every 1 meter of pipe run to allow for the resistance of the hose. As a general rule, the entire volume of the pond should be filtered every 1-2 hours.
3) Often an ultraviolet steriliser is used in conjunction with a filter system. Make sure it is compatible with your filter system and your fish stocking rates, not forgetting that fish will grow. A UV system for a 10,000 litre pond, which is heavily planted, in partial shade and with only a few goldfish will not be able to cope with the same size pond devoid of plants, in full sun with several large Koi carp.
4) When a waterfall is to be installed it will require about 265 litres per hour for every 25mm (1inch) width of the lip of the return to give a thin continuous sheet of water. Again the head and length of hose should be allowed for.
5) Fountain pumps are a straightforward choice and is purely down to your preference of spray pattern and to make sure that all the water falls back onto the pond surface and not emptying your pond especially important in windy weather.
6) As a general rule it is better to have a pump with a greater capacity than you need as it is a fairly simple job to restrict the flow to match your needs but you cannot extract more performance than the pump is designed for.
If you need further assistance with selecting the appropriate size pond pump for your garden pond, please contact a Liners Online representative who will discuss options with you.