How to choose the correct size pond pump

1. Calculate the approximate pond volume

For a rectangular pond, multiply average length × average width × average depth in metres, then multiply by 1,000 to estimate litres. Reduce the result for curves, shelves and rockwork.

2. Decide the required turnover

Many ordinary ornamental ponds aim to pass the pond volume through filtration approximately every one to two hours. Heavily stocked ponds, koi ponds, warm shallow ponds and systems with waterfalls may need different treatment.

3. Check the filter before choosing the pump

Every filter has a flow range or maximum flow. Pressure filters are particularly sensitive: too little flow may give poor circulation, while excessive flow can shorten contact time, reduce performance and create unnecessary pressure. Never assume the filter’s pond-capacity number is its flow rate.

4. Allow for head and hose losses

The box flow rate is normally measured with little or no lift. Real flow falls as water is raised and forced through hose, bends, valves, UV units and filter media. Use the performance curve where available and keep hose generous, short and direct.

5. Set the controllable flow correctly

Fish Mate pond pumps provide flow control. Set the output to the filter’s needs when the complete system is running. Recheck after the filter becomes dirty because restrictions alter real flow.

6. Install with a safety reserve

Raise the pump off the pond floor on a stable support. Secure hoses and waterfall returns against movement and high winds. If water is discharged outside the pond, the raised inlet helps prevent the whole pond being pumped dry.