How to Choose a Swimming Pool Pump in 5 Easy Steps

The swimming pool pump market can appear complicated, so we’ve created five simple steps to help you choose the best pump for your pool.

Many people just replace their old pump with a like-for-like model. However, if your previous pump failed prematurely, it may have been the wrong size or type. It’s worth checking before you replace it.

There’s often a tendency to buy a pump that’s more powerful than necessary. This isn’t recommended, you’ll face higher running costs, risk overpowering the filter, and can even shorten the pump’s lifespan.

The most important thing to consider isn’t the pump’s horsepower (HP) or kilowatt (kW) rating, but its flow rate.

As a general rule, all the water in your pool should be filtered within an 8-hour period.

To choose your Swimming Pool Pump, you’ll need to know:

1. How many litres of water are in your pool

2. The flow rate you need

3. A pump model that meets that requirement

Let’s break that down step by step.

The following steps are a simple guide on how to do this:

Step 1:

Calculate the volume of your pool.

Volume/m3 = Length/m x Width/m x Depth/m

If the pool is not all the same depth, you can use the average depth.

                                                               Same Depth:                                                                                             Different Depths:

Average Depth = (shallow depth +deep depth)/2

Please note these images are for a rectangular pool.

If your pool is circular, you can calculate the volume using the formula:

V=π r²h

Worked Example for Rectangular Pool (same depth):

If you had a 20m pool, which was 8m wide and 1m deep, the Volume would be:

V= 20m x 8m x 1m = 160m3

Step 2:

From step 1 you will be left with a value in metres cubed. This should be converted to litres.

1m3 = 1000 litres.

Therefore, multiply your volume by 1000 to give the figure in litres.

For the worked example, this would be:

160m3 x1000 = 160,000 litres

Step 3:

Calculate the required flow rate to circulate the pool in 8 hours.

As the water must all be circulated in 8 hours, you must divide the figure by 8 to give you the litres per hour figure.

For the worked example, this would be:

160,000L ÷ 8hours = 20000 L/h

Step 4:

Our pumps are rated in litres per minute, so the above figure must then be divided by 60 to give the litres per minute rate which can then be matched with one of our pumps, from either the SMP or SWIMM range.

For the worked example, this would be:

20000 L/h ÷ /60 mins = 333.3 L/m

 You now should have a figure which is the flow rate required in litres per minute. Our swimming pool pumps have this figure detailed.

Step 5:

Select a pool pump from our range of swimming pool pumps which matches your requirements. Ensure the pump has an adequate head for your system.

For the worked example, from the SWIMM range, the SWIMM 1000 would be suitable with a flow rate of 350 Ltr/min:

Please note:

Choosing the right swimming pool pump isn’t just about power; it’s about efficiency and longevity.

A correctly sized pump wi ll save energy, protect your filter, and keep your pool clean and healthy for years to come.

If you’d like help choosing the right pump, you can explore our full range of Swimming Pool Pumps or get in touch for friendly advice.

How to Choose a New Swimming Pool Pump in 5 Easy Steps | Video