What Size Pond Pump Do I Need?

A pond pump plays a vital role in a pond filtration system, ensuring proper water circulation to prevent stagnation. Pond pumps are rated by the volume of water they can circulate per hour (litres per hour, or LPH).

Choosing the right size pump for your pond is crucial for adequate circulation to ensure your pond can support aquatic life whilst also providing enough water flow aesthetically for water features and waterfalls.

Follow our guide to learn more about how to calculate what size pump you’ll need for your pond.

Contents

Why do I need a pond pump?
What size pond pump do I need?

Why do I need a pond pump?

A pond pump is essential for keeping your pond water healthy and in motion.

• Water circulation: Pumps keep water moving, reducing the risk of stagnant water, which can become a breeding ground for harmful bacteria and unwanted smells.
• Filtration: The pump pushes water through your pond’s filtration system, removing debris and impurities to maintain water health and clarity.
• Oxygenation: Pumps ensure adequate oxygenation by circulating the water, which is vital for fish and plants to thrive.

What size pond pump do I need?

To determine the pond pump size you need, take into account these 3 factors:

1. Pond volume = The amount of water a pond holds.
2. Pond pump flow rate = The amount of water a pond pump can circulate in an hour.
3. Pond head height = How high above the pond's surface your pump needs to push the water.

Tip: For ponds with complex or long runs of pipework, friction loss must also be accounted for. If you think this may affect your setup, please seek guidance from the Pond Planet Technical Support team.

1. Calculate pond volume

To start, calculate the total volume of your pond. This helps determine the amount of water the pump needs to circulate.

Use this formula to find your pond volume in litres:

Pond Volume (Litres) = Length(m) x Width(m) x Depth(m) x 1000

Or, for an easier way to calculate it, use our handy Pond Volume Calculator.

2. Pond pump flow rate

The amount of water a pond pump can circulate in an hour is called the flow rate (measured in LPH, litres per hour).

The right pump for your pond should be compatible with your pond volume and how heavily stocked your pond is.

• Lightly stocked ponds: The water should circulate at least once every two hours for ponds with a few small fish or plants. Choose a pump with a flow rate that is half the size of your pond. For example, if your pond is 3000L, choose a pump with a flow rate of 1500 LPH.
• Heavily stocked ponds: The water should circulate closer to once per hour for heavier stocked ponds or those containing koi. For example, if your pond is 3000L, choose a pump with a flow rate of 3000 LPH.

Make sure to choose a pond pump that can still push the required capacity at the head height you require.

3. Calculate head height

Head height is how high above the surface of the pond your pump needs to push the water.

The higher water is pumped vertically, the lower the pump's flow rate, so it is important to factor head height into your calculations when choosing a suitable pump.

Head height is especially crucial if you plan on having a waterfall or water feature to ensure that the pump size counters the height the water needs pushing.

To calculate the head height, measure the height from the water's surface to the highest pumping point, such as the filter or waterfall.

For example, if the waterfall was 1m high from the surface, it would be 1m head height.

You also need to factor in a waterfall or water feature into your pump's required flow rate. As a guide for a standard waterfall we would recommend for every 1cm of waterfall width, you will need a flow of 1.5 litres per minute.

So, if your waterfall is 10cm wide, you would need 15 LPM (litres per minute) x 60 = 900 LPH (litres per hour) as a minimum.

 

Choose the right pond tubing

Small pond pump tubing can restrict the amount of water the pump can circulate, harming your pond water’s health.

Choose the largest pipe diameter your pump can accept for an optimum flow rate.

Shop pond pumps from Pond Planet 

Choosing the right pond pump size is important for keeping your pond healthy. Whether you're looking for a pump for a small garden pond or a larger koi pond, choosing the right pump ensures your pond stays healthy and beautiful all year round.

Shop our selection of pond pumps to find quality options for your pond, with pumps from reputable brands like Oase, Hozelock and Pontec.

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