Should you run your pool pump daytime or nightime – and how long?

A grass field and sky, half is night and half is day.

Pool pumps help to sanitize the pool water, and therefore they need to run long enough to circulate all of the pool water through the filters. The time of day or night you need to run your pool depends on factors such your energy saving needs, the length of time you need to run your pool pump and the pumps’ efficiency among other factors. Experts recommend running the pool pump during the day for 8 hours for efficient pool cleaning and maintenance.

Why do you need to run the pool pump?

Your pool pump helps to pull water and circulate it through the filters which sieve out algae, debris, and bacteria. The pump filters clean and removes trash which is carried through the main drain and into a basket, where the wastes can be discarded. The pumps then circulate this sanitized water back to the pool. Running the pool pump also aids in the distribution of chlorine and the chemicals that are used to maintain the pool’s water ph.

What is the appropriate length of time a pool pump should run?

It is ideal to run your pool pump for as long as it takes to circulate all of the pool water through the filtration system. This duration of time often depends on the size of your pool and pump. On average, pumps usually circulate the entire pool water within 8 hours. With some pumps and some pools, this could take up to 12 hours. 

Are you unsure how long it will take your pool pumps to cleanse your swimming pool and distribute chlorine? You can use a pool pump calculator. Important information you need to know to do the math includes the volume of your pool. Most backyard pools have a capacity of 100,000 liters. 

You also need to figure out the output of your pump. For that, you will need to find out the model number of your pool pump and the length of the pipe leading from the pool’s skimmers and the main drain to the pump. This figure together with the volume of the swimming pool can help you arrive at the length of time it would take to circulate the pool water 

Other factors that affect how long a pool pump should run

Other than the pool pump and pool size, the duration of running a pool pump also depends on:

• The type of pool pump you are using

• whether you use a pool cover or you leave the pool exposed

• The amount of foliage around your swimming pool

• The season of the year and the local climate

• The level of activity the pool gets

• Whether swimmers clean up before diving into the pool

An open swimming pool exposed to light will need longer pumping. The same is the case with pools during the summer or in hot climates, or pools surrounded by many trees that shade leaves. On the same note, a swimming pool that gets used often will also need long hours of cleaning.

How do you increase the efficiency of your pool pump?

If it gets to the point that you are suffocating in energy bills because of your pool pump, there are things you can do to reduce the time needed to achieve a clean pool with pristine waters.

Deal with over-rated pump horsepower

It would help if you had a timer to effectively keep your pool clean and also minimize your energy bill. Whatever intervals or whatever time of day, your pump needs that average of 8 hours to circulate clean water in the pool.
However, if the pump’s horsepower exceeds the size of the swimming pool, the only ideal thing to do would be to reduce the time the pump runs. Data shows that cutting this time by 2 hours can save you up to $10 per month. Just make sure your pool’s condition is not compromised.

First, try cutting down the time your pool pump runs at intervals of 30 minutes every day. All the while you should be checking whether the water quality remains the same. Usually, the difference appears after a week. Doing that will help you find the best pump run time that works well for your pool’s needs and your energy budget.

Put your hands to work

The other thing to do is obvious but often underestimated by many- clean your pool by hand. By that, it means that you can use pool cleaners or vacuum to clear out the dirt and debris from your pool. Doing that eases the cleaning burden shouldered by the pool pumps. It helps them to last longer. Additionally, experts recommend that you empty your pool’s filter baskets daily to prevent clogging in the drains. Clogged drains often cause the pool pumps to work extra harder and use more energy.

Need to save energy? Size (of the pump) matters 

The efficiency of the pool cleaning operation largely depends on the size of the pool pump. Larger pool pumps suck up more energy and might lead to unbearable electricity bills. So when shopping, it would help to first equip yourself with vital pump information.

A home pool generally needs one horsepower (1HP) pump or smaller. If this figure exceeds 1 �, you might need to find yourself a new pump. These bigger pumps work too rapidly for an effective cleaning action through the filters. The good thing with modern day pumps (variable speed pumps) is that you can adjust the flow rate so that the pump cleans up efficiently without excessive energy consumption.

Please do not run the pump for 24 hours, it might keep your pool in pristine conditions, but it will also lead to wear and tear on the pool pump apart from the exorbitant bills. Install a timer on the pump so that you can automatically run the pump at many intervals during the day for maximum efficiency.

The big question: Night or Day?

For many pool owners, choosing to run their pool pumps during the day or during the night is a big debate laden conflicting opinions. Why many people run their pool pumps after dusk is because some cities and counties have lower electricity tariffs at night. However, the question is; what is the best thing for your pool?

What is the best time to run the pool pump?

Many people run the pumps at night, but expert information shows that this could be ineffective. During the day, the sun heats the pool, and as you well know, sunlight is essential for algae survival. Therefore it is safe to say that day time is when you need chlorine to run through the pool. Running the pool pump at night is like an off the hook card for algae colonies. 

You also ought to think about your neighbors. If your pool pump is the noisy type, running it at night could be a nuisance to your neighbors. Every city or metropolitan council have their noise regulation levels. You might want to check with such regulations first or get a quiet pump.

Exceptions – when night time pump circulation might be ideal

Chlorine distributed in the pool at night lasts longer at night than during the day. That is because sunlight often causes this chemical to disintegrate during the day. That might demand that your salt chlorinator runs for longer during the day. It is estimated that running your chlorinator for 6 hours at night is equivalent to running it for 9 hours during the day. Such electricity savings are too significant to ignore.

Apart from the energy savings, nighttime pumping is also ideal when you are doing a chemical treatment. It helps to keep the chlorine levels high.

Day time is best

Your pool’s sanitation is more at risk during the day than it is at night. Aside from the fact that algae thrive under the sun, swimming pools get used the most during the day. Even for homeowners that run their pool pumps at night, most end up running it for a couple of hours during the day too. That could also work. Many pool owners in the Southern states split the time so that they run the pump for four hours in the day and another four hours in the night.

If you are doing the split day and night pool pumping, the best thing is to start at 11 am to around 4 pm when the sun is hot so that it can burn off the chlorine. Another midnight schedule will help you get a good chlorine build-up ahead the next day.

If your chlorine breaks down a lot when you run the pump during the day, you will need to get a chlorine stabilizer. It helps to protect the majority of chlorine so that you don’t need to increase pump run times during the day.


There are advantages and disadvantages for both daytime and nighttime pool pumping. Running your pump during the day when the sun is hot enables you to counteract its effect on algae growth. This is also the time when there are many unseen contaminants brought in by the swimmers. When the UV rays hit the chlorine, it results in a pristine and inviting pool for swimmers.

The choice to run your pool pump during the day or night depends on your personal preference. Generally, experts recommend running it during the day.

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