It seems like a simple question with an obvious answer, doesn’t it? It shouldn’t be difficult to figure out how long to run a pool pump. And really, it’s not.
But before you just turn it on, walk away, and forget about it, you do want to consider a few important factors into account like circulation, chemical balancing, and cost. Especially cost. Because this is one of those parts of pool care that, if you get it wrong, can cost you quite a bit of money.
The ideal answer to this question is all day, every day, all year, all the time, forever.
And then go out and get three more jobs because your electric bill is going to be ridiculous if you do that.
So while that would be ideal, it’s not practical, or even completely necessary. The key is to understand your pool pump’s purpose, the type of pump you have (or could have), and how best to take advantage of its features.
What Does a Pool Pump Do?
If the water in your pool didn’t move, it would quickly become a stagnant swamp, host to algae and all kinds of other yucky stuff. One of the most important factors in keeping your pool clean and swimmable is pool circulation. And that is generated by the pump, which is the first component of your pool’s filtration system.
The pool pump pulls water in, and then pushes it out through the filter. No matter what kind of filter you have, it only works if water moves through it. That’s how the filter is able to capture debris and bacteria.
To keep all the water in the pool clean and clear, it must run through the filter system at least once a day. This is called the turnover rate.
How to Calculate Turnover Rate
First, if you don’t already know it, you’ll need to calculate your pool’s volume. If you’re not sure how to do this, you can use our pool calculator to figure it out:
Once you have your pool’s volume, divide it by eight to determine the number of gallons per hour (GPH) that need to be pumped.
Most pool pumps go by gallons per minute rather than GPH, though. So to get that number, divide the GPH by 60 to determine how many gallons per minute (GPM) need to be pumped for full turnover.
So your formulae will be:
Total Pool Volume ÷ 8 = GPH
GPH ÷ 60 = GPM
Choose the Right Pump
This part’s easy once you have all the numbers. Simply find one that pumps at least the same GPM as is required for your pool. If the one you choose pumps a little more than you need, that’s fine. Just don’t go below your required GPM.
This will ensure your pump will run at the appropriate rate to turn over your pool’s water in one eight-hour period.
Not Just How Long, But When?
Just as important as how long to run a pool pump is when to run it. Sure, you need to run it for at least eight hours. But is that consecutive hours? Daylight? Nighttime? What are we talking about here?
Did you know the rate you pay for electricity changes throughout the day? It’s based on what electric providers call peak hours, meaning when more people are using more power, and putting more strain on the grid.
Peak hours vary from location to location. For example, in warmer climates, peak hours most likely correlate to when people have their air-conditioning cranked, maybe late afternoon or early evening when people are getting home from work and turning up the A/C.
All it takes is a call to your provider to find out the peak hours where you live. Once you know that, try to schedule your pool pump run time around those hours to keep your cost lower.
You can make this really easy on yourself by using a programmable pool timer to turn the pump on and off at the right times.
It may seem logical to have the pump running during the day, while people are swimming in it, so the water stays clean. And that’s a good thought. But consider a couple of other things too.
Those non-peak hours your utility has may be at night, especially if you live in a warm climate where people are more likely to run their air-conditioning during the day.
Also, running your pump is usually necessary after you’ve added chemicals to your pool. In order to get the chemicals dispersed throughout the water, it has to be moving. Otherwise, you may end up with super-sanitized spots and pockets of not-so-clean water, and that’s not the kind of Marco Polo you want to play.
But there’s one chemical that needs to be added at night, or at least at dusk: pool shock. Add it during the day, and the sun will just burn most of it off, reducing its effectiveness.
So when you shock your pool, you’ll definitely want to run your pump at night, and for a minimum of eight hours to fully distribute the shock.
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Yes, you want to run your pool pump for at least eight hours every day to complete at least one turnover cycle. But that doesn’t mean it has to be eight hours straight.
Again, refer to those non-peak utility hours. Working around those, you can run your pump for two hours here, seven hours there, and then three hours there. As long as it runs for at least 8 hours in every 24-hour period, you’re covered.
Not Just How Long, But What Type?
Aside from time of day and non-peak utility hours, how long to run a pool pump also depends on the type of pump you have.
It’s only logical, but it may be something you hadn’t considered. The more powerful your pool pump is—the more horsepower it has—the faster it will turn the water over, which means you can run it less often and for shorter periods of time.
But this is also dependent upon the size of your filter and the filtration system’s pipes. A too-powerful pump can be too much for a small filter. Also, a one-horsepower pump will work more slowly, but if your system uses three-inch pipes, it can accommodate a three-horsepower pump, which will work more quickly.
But there’s another but. Three horsepower can be too much if you have a small pool, and it will only waste energy and cost you more money. Be sure to get a pump that isn’t too powerful for your filtration system, but is powerful enough to turn over your pool’s volume at an adequate rate to hit that magic GPM number you need.
Single, Dual, or Variable Speed
If you have a single-speed pool pump, we recommend you upgrade to at least a dual-speed. You’ll get more efficiency and faster turnover. If you’re going to buy a new pump, we highly recommend you get a dual-speed or better. In addition to the energy savings and better efficiency, some states, such as California and Arizona, actually prohibit the installation of new single-speed pool pumps.
But to really get all the benefits from your investment, we recommend choosing a variable-speed pool pump. They consume less power, help turnover and filtering go more quickly, and you may even be able to get a utility rebate for using one. They also run at lower revolutions per minute (RPM) than single- and dual-speed pumps, so they’re quieter.
Yes, they’re also more expensive. But they’re a long-term investment in your pool’s efficiency and maintenance.
Is Your Pool Pump Running? You’d Better Catch It!
Have you been letting your pool pump run 24/7? Stop the insanity! Now you can look forward to a lower electric bill and turn some lights back on. Or if you haven’t been running it enough, you can look forward to a cleaner pool now that it’s circulating more often.
And the next time you and your neighbor debate how long to run a pool pump, you’ll be armed with good information. Now if you could just get him to trim that tree limb that keep dropping leaves into your pool …
I am Pol Garrett, the head editor here at Pool Supply 360. After a long time of doing pool establishment and support, I decided I should share what i have learned, and that’s why I’m happy to be here at poolsupply360.com