You designed your dream backyard. The pool, the landscaping, the patio. So much effort, and so worth it. You’ve finally crafted a place that not only looks fantastic, but brings a feeling of togetherness for the ones who matter most to you. It's a beautiful thing.
Except you didn't design the aggressive bubbles shooting out of the returns on the pool walls. So what's up with that?
Why are you getting air bubbles in your swimming pool?
This is a common problem, especially when you're first opening your pool for the season.
A few bubbles in the pool or the pump is normal, but noisy churning and lots of bubbles indicate that you likely have a problem.
Quick recap!
Your pump/filter system works like this.
Your pump pulls the pool water from the skimmer(s) on the pool wall and the main drain(s) (if you have one) on the pool floor or lower wall. These components are collectively referred to as the suction side of the pump. Remember that term.
This water hits the first part of the pump, a small sort of filter called the strainer pot. It catches any major debris right away.
After the water goes through the strainer pot, an impeller (non-technical term: spinny thing!) in the pump pushes it on to the filter.
Whether you have a sand, cartridge, or D.E. filter, the water goes through it to remove dirt, debris, and (if the filter is good) bacteria.
After the water is filtered, it flows through the plumbing to the heater/chiller (if you have one) and then the chlorinator (salt chlorine generator or traditional chlorinator) .
The clean water returns to the pool through the aptly named return jets on the pool walls.
Okay, so how does that translate to this issue?
Air bubbles in your pool mean that air is being sucked into the line on the suction side of the pump.
When you first open your pool, you're putting a lot of things back together in the filter system. Nine times out of ten, the issue isn't in the underground plumbing, but in your above ground equipment.
(And above ground issues are often easier to fix because you don't have to dig anything up! Yay!)
River Pools has been a part of the fiberglass/inground pool industry for a long time, and our knowledge and experience along with the chats we have with independent installers across the country allow us to help guide incoming pool buyers and new pool owners from far and wide. And yes, that includes you, even if you end up not buying one of our pools (or even a fiberglass pool)!
So today, we're going to help you troubleshoot your backyard oasis.
So fret not! We're here to guide you.
What are the most common reasons for pool air bubbles?
Air bubbles in your pool mean that air is being sucked into the line on the suction side of the pump. It's likely happening because of one of these issues:
- The pool water level is too low
- The strainer pot lid isn't on tight or its O-ring is loose/absent/compromised
- The union between the valves and the pump isn't tight or its O-ring is loose/absent/compromised
Good news: replacing an O-ring is a DIY fix that often costs less than $50!
1. Is your water level correct?
First, check how high the water is—specifically, in relation to the skimmers.
If the water level is too low, the skimmer will suck in air and send it to the pump/filter system.
What's the proper water level for a swimming pool?
Based on our experience, we recommend you keep the water at least halfway to three-quarters up the skimmer.
NOTE: For fiberglass pools, never drain your pool below the bottom of the skimmer. You'll most likely void your warranty and may even damage the pool. Always hire a professional to assess the need to drain the pool and perform that work for you.
Want to know more about proper fiberglass pool maintenance? Our comprehensive fiberglass pool buyer's guide covers every part of the process, from the factory floor to your backyard -- with tons of tips, tricks, price estimates, and recommendations for long-term care. You can also find some great resources within our fiberglass pool operation/maintenance video library.
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Your pool water should be halfway to three-quarters up the skimmer.
2. Is your strainer lid on tight?
Second, check the strainer pot lid.
It should be closed tight. If it's not snug, you'll suck air right through that lid into the pump.
Check the O-ring under the lid:
-
- Turn the pool pump off.
- Take the lid off.
- Make sure the O-ring is there and in good condition.
- Make sure the O-ring is seated.
- Make sure there's no grit or debris that might be obstructing the lid from getting a secure close.
- Place the lid back into position.
Your strainer lid should have its O-ring in the proper groove, with no damage and no dirt or debris obstructions.
3. Is your pump/valve union on tight?
Third, check the union (fitting) between the pool pump and the valves on the suction side.
Now, this little friend is the most common culprit.
It's where plumbing is taken apart, so it has a pretty high chance for missteps.
Remember the O-ring from the strainer pot lid? Surprise: there's an O-ring here inside the union too!
Check the O-ring at this union:
- Turn the pool pump off.
- Remove the nut over the union.
- Make sure the O-ring is there and in good condition.
- Make sure the O-ring is seated in its groove inside the union.
- Make sure there's no grit or debris preventing the union from closing tightly.
Many times, when you're putting the pump/filter system back together, the union's O-ring will slip out or fall out of its groove. Think about it like a dancer - when you throw it off its groove, bad things happen—like tripping (or in the case of a pool pump/filter system, letting air in).
Reminder: When you tighten your union back up, make sure that the flange (ridge) is flush with the back of the nut. If it's not, something is obstructing the union from fully closing.
The union between the valves and the pump should have its O-ring in the proper groove, with no damage and no dirt or debris obstructions.
Still have air bubbles in your pool?
If you check all 3 of these things and still have air bubbles, you might have a bigger problem—like a suction-side leak in your plumbing, which would be coming from either your main drain or your skimmer line.
That's more than most pool owners want to handle on their own, so call your friendly neighborhood pool professionals. They'll be happy to help!
Side note: Based on the recommendations of builders across the country, using only rigid PVC pipes and plumbing support consisting of both A) gravel backfill and B) plumbing straps may help prevent plumbing leaks right from the beginning.
Want to learn more about pools?
Bubble troubleshooting isn't all we're good at.
In our blog and our YouTube videos, we cover all the most common questions about pools—and some of the more obscure questions, too.
We're big proponents of fiberglass pools, obviously, although we know that they aren't the best fit for every situation. While the shapes and sizes are less customized, most people can find a model that fits their needs.
The aesthetics, longevity, and lower maintenance compared to other inground pool types make them a huge win in our book.
Made it here but don’t have a fiberglass pool of your own yet? Get in touch with us and we’ll help connect you with an independent installer in your area. Happy swimming!
Up Next:
How Long Should I Run My Pool Pump?
The Ultimate Guide to Inground Swimming Pool Maintenance
Fiberglass Swimming Pools 101: Manufacturing, Cost, and More
Editor's note: This blog article was updated on January 27, 2020.
Editor's note: This article was originally written by Holly Jender and was updated on November 20, 2023, with current information. River Pools is a brand of inground fiberglass pools produced via the River Pools division of the manufacturing facility in Fortville, IN. While our expertise is in fiberglass pools, we have a network of expertise relating to all things inground pools. Our own collective experience from over the years spans manufacturing, project design, installation, and pool service. We often tap into this knowledge base and share information freely with homeowners, just like you, who are considering having a swimming pool installed in their backyard.