You’ve installed the pool of your dreams in the backyard, and you want the water to stay clean and crystal clear. But you don’t want to get a second job to be able to afford to keep your pool pump running 24 hours per day. You wouldn’t have any time left to enjoy your pool! So what’s the perfect balance — how often do you need to turn over your pool water to keep it fresh without blowing up your electric bill?
As a general rule, you should run your pump for 8 hours per day. All of the water in your pool should be filtered at least once every 24 hours, and with the right pump, you can safely assume that 8 hours per day will keep your pool clean.
But for those of you willing to do a little math (and we’re talking multiplication and division — not calculus), the answer is a little more complicated. The size of your pool and the type of pump you have will dictate exactly how much you should run your pump, and you might even discover that a different model would save you money over time.
How Often Should You Turn Your Pool Over?
Your pool’s filter is all that’s keeping your pool from turning into a green, algae-filled swamp, and your backyard from becoming a mosquito breeding ground. Not exactly what you had in mind when you installed your pool, right? But if you’re not running your pump, your filter can’t do its job.
As you run your pump, your pool water cycles through your sand filter, catching bacteria and debris (and the occasional toy) on the way in and helping to disburse your cleaning chemicals on the way out. It’s doing the work that currents and tides naturally do in the rivers and lakes we like to swim in (unlike that algae-filled swamp!)
In an ideal world, you would just keep your pump running constantly and never let your pool water sit still. But unfortunately, running your pump isn’t free. You’ll be able to keep a clean and good-looking pool and avoid breaking the bank, by making sure all the water runs through your filter at least once a day.
If your pump is the right size for your pool, running your pump for 8 hours per day should accomplish this. But if you have a more powerful pump, you might be able to run it less. Ultimately, you’ll want to calculate your own turnover rate for your pool and pump.
How to Calculate the Turnover Rate for Your Pool
In order to establish exactly how long to run your pump for each day, you’ll need to research how much water your pump is supposed to move every hour and compare that to the volume of your pool.
Find your pump’s turnover rate or GPH (Gallons Per Hour) and multiply that by 8 to see how much water your pump filters in 8 hours; then calculate the volume of your pool. If those two numbers match, you have the right sized pump, and running it 8 hours per day will keep your pool clean.
Some pumps list turnover rate in GPM (Gallons Per Minute); simply multiply by 60 to get GPH.
[Pump GPM] x 60 = [Pump GPH]
Then to see how much water your pump processes over 8 hours multiply your GPH by 8.
[Pump GPH] x 8 = [Water pumped over 8 hours]
Ideally, that number matches the volume of your pool, and you can comfortably commit to running your pump for 8 hours per day.
[Pump GPH] x 8 = [Pool volume]
If you’re not sure about the volume of your pool, luckily that’s also a fairly simple calculation. If you have a rectangular pool, multiply width, length, and depth to find the area in cubic feet, and then multiply that by 7.5 to get the area in gallons.
[Pool width] x [Pool length] x [Pool depth] x 7.5 = [Pool volume in gallons]
If you have a round pool, substitute diameter for length and width.
[Pool diameter] x [Pool depth] x 7.5 = [Pool volume in gallons]
So after all that math, what if your pump’s GPH and your pool’s volume don’t line up? I have one more simple calculation for you. Divide your pool’s volume by your pump’s GPH, and you’ll come out with exactly how many hours you should run your pump for.
[Pool volume] ÷ [Pump GPH] = [Hours per day to run your pump]
If you got 7.85 hours, you can probably just run your pump for 8 hours and not overthink things. But if you got 5 hours or 13 hours, you could be wasting some serious money and possibly even doing damage to your filtration system.
How to Choose a Pool Pump
Having the right tool for the job is just as important in pool filtration as it is everywhere else, and spending a little extra initially to get the best technology will likely save you money over time.
Usually, the most important factor in choosing a pool pump is getting the right GPH (or turnover rate). However, you’ll also want to find the right pump speed and horsepower for your filtration system and your budget.
Horsepower, or how powerful your pump is, can help you move water through your filtration system more quickly (which means spending less money on your electricity bill). But don’t get excited and try to install your old pickup’s motor in your pool pump yet; too much horsepower can overwhelm your filtration system by pushing too much water through your filter and pipes — more than they can handle. Unless you want to upgrade the whole system, stick with horsepower that will push the right amount of water through in that 8-hour window.
There are three different types of pump speed: Single Speed, Dual Speed, and Variable Speed.
Single Speed and Dual Speed pumps are fairly self-explanatory; they spin at 1 or 2 speeds respectively. They’re cheap to buy, and they get the job done, but they often spin faster than necessary (which means more money on your electricity bill). Single Speed pumps are so inefficient that some states like Arizona and California prohibit their installation.
Variable Speed pumps are the Cadillacs of the pool pump world. They consume less power (cheaper!), they move water faster, and they make less noise because they’re spinning slower, so you can leave your pump on during the BBQ. While they’re more expensive upfront, most Variable Speed pumps will pay for themselves in under 2 years in utility savings.
Your neighbors may never see it, but knowing you have the right pump in place for your pool, your filtration system, and your electricity bill will make it so much easier to float your weekends away, worry-free.