Choosing a Pump for your Pond by Philip Swindells

The success of any moving water feature is dependant upon a suitable pond pump. The water flow rate of the pond pump is particularly important, for it is this upon which the water feature depends for its visual effect. Irrespective of the model of pump selected, be certain that it produces a flow rate that is greater than the current requirement. Spare capacity is invaluable for permitting adjustments and modifications to be made in the future.

Most modern pond pumps for the water garden have a small discharge, so it is essential to know how much water it is going to be necessary to move in order to create the desired visual effect, before a pond pump selection is made. The importance of having sufficient outflow cannot be over-emphasised.

The majority will produce a satisfactory fountain, but a considerable amount of water is necessary to create an effective waterfall, and a pump of generous capacity is required to ensure a successful fountain and waterfall combination. With a waterfall, most average pre-formed cascade units will require an output of at least 300 gallons per hour to put a thin sheet of water across their width, while 360 gallons per hour is necessary to make a continuous filmy flow 6ins wide.

To test for specific pond pump capacity requirements, run water into the upper pre-formed unit of a waterfall or stream from a hosepipe and adjust the flow until the desired effect is produced. Collect the water that passes over the unit for the period of one minute. Measure the quantity of water collected and convert into gallons. Multiply by 60 to give the amount of water that the pond pump will be required to move per hour. Then check the flow rate necessary against the pond pump manufacturer's recommendations.

The majority of pond pumps used in water features today are submersible pumps. They consist of a self-contained sealed unit that draws water through a simple pond filter and pushes it out through an outlet pipe. The pond filter unit collects any particles of debris in the water and must be periodically removed and cleaned. The submersible pond pump will be fitted with a waterproof cable that will extend well beyond the edge of the pond for attachment with a waterproof connector.

Some gardeners who have large water features, or fish-keepers with high water movement requirements and who need a very powerful pond pump, will choose a surface pump, which is then housed in its own chamber constructed alongside the pond. This is usually a modest brick structure closed in by a paving slab, which is removable for access.

About the Author

Philip Swindells has over 40 years gardening experience. A former botanical garden curator and an international horticultural consultant, he has worked extensively overseas. The Author of more than 50 gardening books, he has been awarded a Quill and Trowel Award by the Garden Writers' Association of America. He is also a former UK Garden Writer of the Year. He is currently editor of http://www.internationalwatergardener.com