Pool Circulation 101: What It Is, How It Works, and How to Make Yours Better

If you’ve maintained a pool for a while, you know that the secret lies in precision. For example, nobody shrugs their shoulders, pours in an entire bucket of sanitizer, and doesn’t lives to regret it. DIY maintenance is all about doing just the right amount of treatment and work for your pool to keep it happy and functioning—without it taking over your life. And one major way to achieve a functioning, low-maintenance pool lies in one big word: circulation. Every pool needs it, and needs just the right amount.

And this is why precision is key: although too much circulation will result in higher energy bills, too little will result in higher maintenance costs, such as eradicating algae, fixing scaling on your pool walls, and even medical bills for swimmers. Oof. That’s why I’ll explain what circulation is, why it’s important, how it works, and finally, how to optimize the circulation of your pool. This is a fundamental lesson every pool owner should know. So better make a move on!

What Does Circulation Mean?

Just like your heart circulates blood throughout your body (weird to say, but it’s true), your pump circulates water throughout your greater pool circulation system. This should include every bit of water that exists in your pool. But in order to move on and get specific, there’s a few terms that we should get down pat first. 

Flow Rate

The flow rate is how quickly circulation happens. Basically, it’s the speed of your water moving through your system. This is usually thanks to the settings on your pump—though you don’t have too many options if you have a single-speed pump, and not a variable-speed pump. How long you run your pump depends on your flow rate.

Turnover Rate

The turnover rate is how number of hours it takes for the total volume of your pool water to pass through your filtration system and return back to the pool. Typically, it’s between six and eight hours, and allows water to be circulated a few times per day. The goal here is to make sure your total volume of water circulates three to four times a day, not just once.

Variable-speed pumps allow you to choose the horsepower and flow rate that’s right for your pool—and save a ton of money to boot. The 1.5 HP Variable Speed Blue Torrent Thunder In-Ground Swimming Pool Pump—it pays itself off in under a year, is eligible for rebates, and also comes with a warranty. As customer Eric D says, “Day one, I fired this pump up and it ran clean and fast.”

pool circulation

Why Circulate at All? 

If you’re shrugging your shoulders at circulation in the first place, I’m going to need to ask you to stop right there and picture the last swamp you’ve seen, complete with murky green water and a bobbing duck or two. Yeah, that’s what your pool will be without circulation. Although it’s tempting to not have to spend any money on equipment and your monthly energy bill, it’s going to cost you a lot more in the not-so-long run to turn that green mess back into a swimming pool

Okay, so there’s your worst case scenario. But in order to have a truly healthy pool, we have to move beyond whether or not to circulate. The real question here is how much circulation you actually need. Basically, every drop of water in your pool should be moving through your greater circulation system at least a few times every single day. It’s essential to determine how long to run your pool pump so that you’re right on the money—and I’ll help you take it even further in a few.

There are two main reasons why circulation is so important to keeping your pool sparking clean, and they sound a lot like each other: filtration and disinfection.


Thanks to circulation, your pool water rushes through a filter, which then removes particles and debris. Proper filtration means that you won’t need to add chemicals as frequently to your pool as you would have to otherwise. It also means that the microscopic contaminants that are big enough for your filter to catch won’t be swimming in the pool along with you. Since some of those contaminants could potentially make you sick, it’s also an issue of safety. Get that bacteria out of here.


All those chemicals that you do add to the pool? Well, in order for them to work properly, you want them to be evenly distributed across your pool water. Since too high or too low concentrations of any chemical you add to your pool could be hazardous to swimmers or the pool itself, the last thing any pool owner wants is saturated pockets of chemicals while the rest of the water is completely unaffected. Making sure that all chemicals is circulated properly is one of the foundational steps to maintaining chemical balance and a safe pool. This is especially true for sanitizer. Don’t make me use that “b” word again (bacteria!).

How Does a Pool Circulate Water?

Get ready to make a mental flow chart. This is a continuous cycle, but not one of those couple’s-therapy types. This cycle keeps your pool clean, balanced, and safe.

1.     First, your pump sucks in water from the pool through the skimmer, which is usually a rectangular port in the pool wall. This skimmer sort of looks like the hole in your sink that keeps water from overflowing—but in this case, you always want water to be above the skimmer so that it can suck in water and water only.

2.     Next, water passes through the pump’s strainer basket, which catches large debris like leaves. It also passes into the filter, which cleans the water of microscopic debris and contaminants.

3.     Finally, the water passes out of the filter and back into the pool through the pool jets—those would be the little circular pieces embedded in your pool wall. You’ve probably seen or felt them pushing water out when the pump is on. Make sure you angle these toward what pool experts call “dead areas,” such as behind ladders, around the pool steps, and underneath the skimmer. These are usually pockets with poorer circulation than the rest of your pool. 

I’ll say it again: ideally, this process involves every drop of your water, and repeats a few times per day.  

pool circulation

How to Make Your Circulation More Efficient—In Five Ways 

Now that you understand why circulation is such a central part of having a swimmable, safe, and cost-saving pool, you’re ready to take yours up—or down!—a notch. Here’s how to make your circulation way more efficient. This is going to be a breeze once you get going. 

1.     The Size of Your Pool Is Step One

Before we take it any further from here, you’re going to want to make sure you know exactly how many gallons your pool contains. Without understanding how much water you need to move, you’re going to have a pretty tough time calculating how long your pump needs to run to achieve the right amount of circulation. And if you’re already running a pump for as long as you think it needs to run without having calculated your pool size, there’s a big chance you’re losing money in the long haul.

Knowing your pool size will save you a lot of money on your pump and your energy bill, but it’ll also help you find the perfect heat pump, like the Energy-Saving ComforTemp Pool Heat Pump 95,000 BTU to heat 18,000 Gallons. According to customer Steve, “Simple install and simple set up. Heated my pool from 66 to 82 degrees in about 2 complete days.” 

2.     Nail How Long Your Pool Pump Runs

Now that you know your pool size, you can calculate how long your pool pump needs to run for proper circulation. The secret to this one is in your pump. How many gallons per hour does it claim to move? You want to multiply that by eight and see if it’s well above the total volume of your pool. If it’s below, you’re not getting nearly as much circulation as you need.

3.     Everything Goes Back to Power 

We’ve already covered that your flow rate is determined by your pool pump, but you don’t have to do too much guessing beyond that. That’s because the answer lies in your horsepower. If you have a lower horsepower, your pump’s flow rate will be slower. If you have a higher horsepower, your pump’s flow rate will be faster. If your pump is running for eight hours but isn’t circulating as much as it needs to during that time, you’re going to need a higher horsepower. You can also just run the pump for way longer, but then it’s your energy bill that might suffer. Sorry about that.

4.     Check Your System for Clogs 

Nothing ruins both the flow rate and the turnover rate like water pushing through your system carrying large pieces of debris. That debris will can get stuck in your system and block the way for water to rush through. Your water might still find a way around the clogs, but it’s going to be significantly slowed down—and the amount of power it needs might seriously heat up your pump.

You should be frequently checking your pump’s strainer basket—just make sure your pump is off first (that includes automatic timers). Your skimmer also has a strainer nearby, which looks like a colander in a little bucket. Ideally, you should clean these out every day or so. If there’s a clog elsewhere in your system, then that’s a different story.

5.     I’ve Said It Before: Get a Variable-Speed Pump!

I might sound like a broken pool jet here, but getting a variable-speed pump is the best decision any pool owner can make. Variable-speed pumps can be adjusted to accommodate your pool’s needs. And they’re just way better—they circulate more thoroughly, can be adjusted for the size of your pool, and will save you a ton of money. In fact, they usually pay themselves off in energy saved in under six months. Since they’re so good for the environment, they’re going to become virtually federal law for all pool owners in the United States starting in 2021. Plus, they’re often also available for rebates. Visit our rebates calculator to see how much money you’ll save—but remember, every energy bill that comes in is another opportunity for saving big. I’m ending this circulation lesson with the best advice: get a variable-speed pump. But ultimately, the choice is yours.

My top variable-speed recommendation? The Blue Torrent 2 HP Variable-Speed Pump is ultra-powerful, comes with a lifetime warranty, eligible for rebates, and pays itself off in under a year by energy saved. It also tops the market in genius design. As customer Bill Britton says, “Runs great. Super quiet.”

pool circulation

Keep It Moving!

Another day, another opportunity to make sure your pool is getting the circulation it needs. But now that you know the basics, you’ll save a ton of money. No more spending extra on your energy bill for circulating too much, and no more spending extra on maintenance for circulating too little. You’ve just located the money-saving middle, and you’re good to go. Now that you know you’re not wasting money or energy, take a refreshing dive. Ahh. That’s responsible pool ownership right there. Enjoy.


Read more on whether you should run a pool heater overnight. Want to know how to heat your pool in an efficient way? Read more here.

Above ground poolAbove ground poolsIn-ground poolsPoolPool accessoriesPool equipmentPool maintenance