Keeping your pool clean ensures it’s safe to swim in, making it the perfect way to cool off on those long summer days. As a pool owner, it’s important to note that your pool pump is essential to keeping the water clean. Even if you’re diligent about adding chemicals, without regular circulation from the pump, water can become stagnant, leading to the growth of harmful microorganisms. Let’s break down how long you need to run it to keep your backyard oasis looking pristine:
Water Volume And Pump Capacity
Knowing your pool’s water volume is the first step in figuring out how long you need to run your pump. Get out your measuring tape and calculator, and use the following equations:
- Volume = Length x Width x Average Depth
- Then, convert the volume to gallons by multiplying: Gallons in your pool = Volume x 7.5
If your pool has a shallow and deep end, use the average depth. To find that, add the depth of both ends and divide by two.
For Circular Pools
To find the volume for a circular pool, you’ll still need to know the depth, but you’ll also have to find the radius, which is the length from the middle of the pool to the edge. You can also measure this by finding the diameter or width and dividing it by 2. Once you have that number, use this equation: Radius² x 3.14 x Depth = Volume
Understanding The Turnover Rate
To keep the pool fresh and ready to dive in, all the water in it must go through the filter at least once daily. This process is called the turnover rate, and that’s the final number we need to find. A standard pool pump takes eight hours to circulate the entire volume of water through the filter once, which is how we calculate the necessary gallons per hour (GPH) your pump should handle: Volume / 8 = GPH
Let’s assume your pool holds 18,000 gallons; you’ll need a pump with a capacity of at least 2,250 GPH. Pump speed and efficiency are measured by the number of GPH the pump can filter effectively. So, when choosing a pump, you’ll need to find one with a GPH of 2,250 or higher. If you encounter pump specifications in gallons per minute (GPM), simply divide the required GPH by 60.
Single-Speed vs. Variable Speed Pumps
Most pool pumps installed in Ottawa today are single-speed, but variable-speed pumps have become a popular option. As the name suggests, a single-speed pump runs at a single speed, using the same amount of energy at all times just to keep water moving. A variable-speed pump can slow down without sacrificing filtration, thanks to the Pump Affinity Law: energy use drops dramatically as flow rate decreases, even when the pump runs for more total hours.
In practice, this can mean a variable-speed pump uses as little as 2.2 kWh to turn over the same volume of water that a single-speed pump uses 12.6 kWh. Over a full swimming season, that difference adds up fast. Many homeowners see a payback period of under two years, with variable speed pumps often costing hundreds of dollars less to run annually once the higher upfront cost is factored in.
Time of Day
If you aren’t sure when to run your pump, look up your city’s or hydro provider’s non-peak electrical hours—that is often the best time of day for homeowners. This is usually in the evening or overnight.
On the other hand, you may also want to run your pump right after you shock your pool to help distribute the chemicals. If it isn’t convenient to run it for the full eight hours, don’t worry. You can run it for an hour in the morning and the remaining seven hours in the evening after you add the chemicals.
In Ontario, many homeowners are on Time-of-Use hydro pricing, and the gap between rate periods is significant. Off-peak hours, weekdays from 7 p.m. to 7 a.m. plus all day on weekends and holidays, are billed at close to half the rate of on-peak hours. For a pump that needs to run eight hours a day regardless of the season, shifting that runtime to off-peak hours is one of the simplest ways to lower your pool’s contribution to your hydro bill without changing anything else about how you maintain it.
A Seasonal Run-Time Guide
Your ideal run time isn’t static; it shifts with water temperature and pool usage throughout the year. Here’s a general breakdown to use as a starting point.
|
Season |
Typical Run Time |
|
Summer (peak use, warm water) |
8-12 hours per day |
|
Shoulder season (spring and fall, cooler water) |
4-6 hours per day |
|
Winter (pool open, minimal use) |
2-3 hours per day |
Use these recommendations as a general guide, not a strict formula. Every pool is a little different, so factors like its size, your pump, and how quickly leaves or other debris build up may mean you need to run it a bit longer or shorter. If the water stays clean, you’re probably on the right track.
Pay Attention to Water Quality
One of the easiest ways to tell whether your pump is running long enough is to look at the condition of the water. If it stays clear, debris is being collected properly, and your chemical levels remain stable, your current schedule is probably working well. On the other hand, cloudy water, floating debris, or algae starting to develop can be signs that the pump isn’t circulating the water for long enough. It might also mean it’s time to clean the skimmer basket or filter. Checking these things regularly will help you fine-tune your pump schedule while keeping your pool looking its best.
What About The Off-Season?
Closing up your pool before cooler weather is necessary for Ottawa pool owners. Because it gets so cold here, you only have to run the pump if you have an indoor pool, as any outdoor pool will freeze regardless of whether the pump is running or not. However, you will not have to run the pump if your pool is fully winterized. As a general rule, if there is still water in the basin, running it for two to three hours a day is recommended.
In the winter, your pump can help prevent bacterial growth and keep your pipes from freezing, which is important when it comes time to open your pool back up in the spring.
Optimizing Pool Pump Run Time
Now that you know how long you should run your pump in the on- and off-seasons, you may be wondering: can you run it for too long? The simple answer is no. Nothing bad will happen if you forget to turn it off after eight hours.
If your pool still has a single-speed pump, upgrading is often easier to justify than most homeowners expect. Although a variable speed model costs more to buy, it uses far less electricity and can run for longer periods at lower speeds, improving circulation without driving up your hydro bill. If your current pump is nearing the end of its life, replacing it with a variable speed model is usually the better long-term investment.
At Benson Pools, we have over 50 years of experience installing and providing pool maintenance in the Ottawa area. If you’re trying to determine the best pool pump for your backyard oasis, need a hand measuring the water volume in your pool, or have any other questions about pool services, we’re here to help. Contact us today.
