Optimising Swimming Pool Circulation

Nov 23, 2020 | Pool Advice

Swimming Pool Circulation

It’s a bit of a joke in the swimming pool industry; “what’s the difference between a pool and a pond?” Well, the answer is that a pool has circulation and filtration and a pond does not. It’s not exactly funny but it is true. Swimming pool circulation is an important element to get right if you want a healthy swimming pool – or spa pool.

Why is swimming pool circulation so important?

Circulation is the movement of water and filtration is the removal of debris from the water. Your pool should be set up with a pump and a filter installed. The pump is responsible for drawing water from the pool, pushing it through the filter, and then back to the swimming pool. This circulation is essential to keeping your water clear and healthy.

Pool Return Inlet

The purpose of swimming pool circulation is to move the water in a cycle around all of the filtration and chlorination equipment and back to the pool. Circulation helps to ensure the sanitiser and other chemicals are dispersed evenly. It keeps a consistent water temperature in the pool and helps to avoid ‘dead spots’ in the pool where water can sit undisturbed and potentially collect bacteria and debris.

How to maintain good water circulation

During the swimming season, you should generally run your pump between 8 to 12 hours daily depending on the pool usage, water temperature, and climate. If in doubt it is better to run your pump for longer as you can never over-filter your pool. We do have a number of clients who run their pump 24 hours a day, 365 days of the year as it just looks so good with all the circulation and filtration.

It’s good practice to point your return jet or jets (this is the place where the water comes into the pool) in a direction that will spin the water in your pool. The jets should be pointing downwards at a 45-degree angle. This helps to circulate the water and also mix the water on the bottom of your pool up to the surface. Jets that point straight out from the wall do not cause any mixing of the water in the lower portion of the pool.

Spa Pool Circulation

Maintaining the correct water level in the pool is also important for ensuring optimal circulation. The water in your pool should be about 1/2 to 2/3 of the way up the skimmer. Never ever let the water level drop below the skimmer when the pump is running. If the water has dropped below the skimmer no water will be flowing to the pump and the pump is doing what is called ‘running dry’.

If left running dry for long enough the pump will overheat, internal parts of the pump literally start to melt and in the worst-case scenario, the pump could begin to smoke and burn.

If you don’t have a skimmer, you simply need to ensure that your water level is always above the outlet where the water leaves the pool and goes to the pump and filter.

Swimming Pool Steps

Check for areas where there is no circulation

We call areas in your pool that have poor or no circulation ‘dead areas’. Algae, bacteria, and debris can accumulate in dead areas. You need to be aware of these areas (if you have any). Dead areas are commonly found behind ladders, around pool steps, beneath the skimmer, and in any imperfections of the pool surface.

Do your best to point your return jets to improve these areas but if you can’t eliminate them you will just need to give these areas a little more of your attention. Using your pool broom to brush the area will help to push debris into other areas of greater circulation and prevent algae from taking hold.

Using your pool regularly will also help to improve water circulation, particularly if people are using the whole pool and stirring up the water by swimming, jumping, and playing in the water.

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