How to Get Algae Off the Bottom of Your Pool

Algae in pools often result from poor circulation, heavy rains, or low chlorine levels. Learn to quickly remove algae and enjoy a clean pool for family swimming.

how to get algae off bottom of pool

Algae at the bottom of pools most often occur from poor circulation. But heavy rains and low chlorine levels also contribute to its growth.

And while it’s frustrating, algae blooms sometimes happen no matter what safety and cleaning measures you employ. So thankfully, we will show you how to get algae off the bottom of your pool quickly. And then your family gets back to swimming in no time! 

Disclosure: As an Amazon Associate, this site earns from qualifying purchases. Thank you!

Getting Algae off the Bottom of Your Pool: Step by Step

You only need to follow a few steps to clean the algae from your swimming pool. And you’re probably already doing most of this pool maintenance.

Hey hey – real quick! Don’t forget to subscribe to get our best content 🙂

Of course, regular attention reduces the chance of algae growth, but here’s what to do once it starts.

Step 1: Scoop out Organic Debris

Use a net to scoop out organic debris, like leaves and insects. Regular scooping means your filter works more efficiently on the smaller organics.

Think of netting debris as a zen practice, so you’ll get in the daily habit of pool cleaning during the swimming season.

Step 2: Test Your Pool’s Water Chemicals

what does alkalinity do for a pool

Now test the chemical levels in your pool’s water. Maintain an ideal pH range from 7 to 7.6, because if pH levels rise above 8, they lead to skin rashes. In contrast, low levels might burn a swimmer’s eyes. 

Regular chemical checks lead to healthier swimming pools, so staying on top of your levels helps prevent algae growth in the first place.

However, even the cleanest pools are prone to algae growth after heavy rains or temperature spikes. 

Step 3: Restore Balance and Kill the Algae

Kill the algae by first shocking the water with an algaecide. Follow your brand’s instructions for the best results but generally, resort to chemicals when first seeing signs of algae growth.

Select a non-foaming algaecide to keep your water clear. Also, algaecide with metals may stain your pool’s walls and bottom. So select a metal-free compound.

Some pool owners forgo the algaecide in favor of adding additional chlorine. Either option shocks the water, so follow your standard maintenance practices.

Either way, chemical rebalancing is a significant step in how to get algae off the bottom of your pool.

Step 4: Scrub Your Pool’s Surfaces

how to get rid of backswimmer bugs in pool

The next step in getting algae off your pool’s bottom requires a bit of scrubbing. After the chemical shock, your crystal clear water shows every algae location. So grab your pool brush and start scrubbing.

Pay special attention to areas with lower circulation, like around your ladder, pool lights, and grout lines. These areas tend to harbor algae spores, so give them an extra scrub.

Use your net to scoop any large clumps where possible. However, algae often separate into fine particles, so scooping may prove difficult. Continue brushing your pool’s surfaces, paying particular attention to any grout lines or crevices.  

Step 5: Vacuum and Filter Algae From Your Pool’s Bottom

The final steps to get algae off the bottom of your pool are vacuuming and filtering. First, consider letting the water settle after scrubbing for a clear line of sight. Then vacuum to remove any loose algae resting on the pool’s floor.

And finally, run your pool’s filtering system for 12 to 24 hours after this rigorous cleaning. Remember to check and clean the filter itself before and after this process. 

What if you don’t have a pool vacuum?

If you don’t have a pool vacuum, don’t fret. First, follow the same steps to scoop out organic particles. Then chemically shock the water.

Finally, give your pool walls and floor a good scrub before running your filtering system for 12-24 hours to clear the algae. 

Then, ideally, run your filter for at least nine hours per day during the swimming season. Regular chemical checks and filtering are the best ways to get algae off the bottom of your pool. 

How To Get Different Types of Algae Off the Bottom of Pools

Three types of algae most often occur in home swimming pools.

Green Algae

Green algae vary in color from pale to dark green. This is the most common and the easiest algae to manage, so that’s the good news.

However, it often blooms overnight, so don’t be too surprised if you wake to murky green water with mossy algae clumps.

The algae grow along the pool’s surfaces, clinging to areas with low circulation. 

However, once you’ve killed this type of algae, it sinks to the pool’s bottom, creating a slippery mess. And that’s why you scoop organic debris, vacuum, and run your filter to clear out green algae.

Mustard Yellow Algae

Pool owners may also see mustard-yellow algae formations. Mustard algae cleans up reasonably quickly but may require several treatments to rid your pool of all traces. It mainly grows in areas of poor circulation, like inside light fixtures and behind the ladder.

Mustard algae resist chlorine treatments, but an algaecide usually knocks it down. A good brushing before chemical treatment ensures a better chance of effectiveness. So scrub all the nooks and crannies for the best results.

Black Algae

Stubborn black algae also require vigorous scraping and brushing for removal. But luckily, it’s the least common type of algae in home swimming pools. Usually, black algae pop up as small dark blobs that are hard to scrape off. 

Its root-like filaments grab onto your pool’s surface and bury themselves. It sounds like a lousy Sci-Fi villain but take heart. 

Thorough scrubbing and spot applications of granulated chlorine make haste in cleaning black algae from the bottom of pools. And, since spot treatments penetrate deeply, the black algae don’t stand a chance. 

What To Look for When Checking Your Pool

Giant algae blooms are noticeable right away. But you also want to take stock of your pool regularly. And then take any necessary steps toward water treatment before blooms occur.

  • Is the water clear or cloudy?
  • Can you clearly see the pool’s bottom?
  • Did you recently experience heavy rains or extremely high temperatures?
  • Has the neighbor’s dog jumped into the pool again?
  • Did a windstorm sweep flying leaves, dust, or debris into the pool?

Keeping an eye on the general health of your swimming pool’s water goes a long way toward preventing algae blooms. 


If you still have questions about algae in your pool, keep reading. We cover all the details, so you can concentrate of family time!

How does algae form in a pool?

Algae is a constant presence in the water. But since it’s microscopic, you don’t see it until it “blooms.” That’s when it feeds upon water conditions to grow and multiply. Most algae blooms occur when your pool’s chemical levels are off. Causes include:

  • Heavy rains when the chemicals become unbalanced
  • Poor chemical maintenance (deficient chlorine levels) and cleaning practices
  • High outdoor temperatures warm the pool’s water, creating ideal conditions for algae growth.
  • Poor water circulation, especially around the ladder, lights, and in corners
  • Heavy pool use means dead skin cells, suntan lotions, pet hair from swimming dogs, and other contaminants enter the water. This potential overuse creates a hotbed for algae growth.
  • Dead animals, like lizards, insects, or frogs
  • Organic debris, like leaves or twigs

So you can see from these examples that algae growth doesn’t mean you’re a terrible pool owner. Instead, algae exist in your pool, waiting for perfect blooming conditions.

Can you swim with algae in the pool?

For each algae type, keep your family out of the pool during the cleaning and sterilization process. The algae typically don’t pose much health risk but a couple of pool-less days is better than chancing it. 

The biggest worry is reduced visibility due to murky waters. But ingesting algae might potentially cause intestinal distress, like diarrhea or vomiting.

You might read about a local lake or river closure due to algae blooms. So it’s natural to worry about health risks from swimming pool algae. But toxin-producing algae are more likely to occur in natural water bodies than in chemically treated pools.

Are pool chlorine products worse for you than algae?

Some pool owners prefer using the fewest amount of chemicals possible. And that’s understandable since we’re discussing your family’s health. However, pool chlorination sparks many debates about the potential health issues caused by the chemicals.

Educating yourself improves your comfort level with the products used in your pool. So once you learn all you can about the chemicals you’re using, you’ll feel more confident. And you’ll know that you’re keeping your family safe. 

Regular maintenance goes a long way in how to get algae off the bottom of your pool. So you and your family will enjoy splashing your way to great memories.

More FAQs

Do you have to vacuum dead algae out of a pool?

You do need to manually vacuum dead algae out of a pool after treating for algae.

Does algaecide really work?

Algaecide’s effectiveness is generally acknowledged, although the exact mechanism behind its efficacy remains uncertain. It is worth mentioning that if you reside in a region with elevated metal levels and have filled your pool with such water, there is a potential risk of oxidation, which can result in pool staining.

Why am I getting algae on the bottom of my pool?

You are getting algae on the bottom of your pool due to factors such as inadequate filtration, imbalanced water chemistry, insufficient or fluctuating chlorine levels, and inadequate water circulation.

What naturally kills algae in a pool?

Sodium Bicarbonate or Baking Soda can naturally eliminate algae in a pool, but caution must be exercised when using it. Excessive use of this cleaning agent can disrupt the pool’s alkalinity, potentially causing various pool issues in the future.

How long does it take to get rid of algae in a pool?

It takes approximately 3 to 4 days to eliminate algae in a pool by raising the chlorine level and maintaining it at a high level until all the algae is eradicated. To expedite the process, it is crucial to run the filter continuously for 24 hours a day and consistently maintain the elevated chlorine level.

What algae won’t brush off?

The algae that won’t brush off is Yellow Pool Algae or Mustard Algae. It is resistant to normal doses of sanitizer or algaecide, such as chlorine. To effectively eliminate it, you must super shock your swimming pool; otherwise, you will continuously struggle with it throughout the entire season.

Will chlorine kill algae on bottom of pool?

Chlorine is an effective method for eliminating algae on the bottom of a pool. A super-chlorination treatment with 10-20 ppm of chlorine can greatly assist in eradicating the algae. Liquid chlorine is particularly suitable for this purpose as it acts quickly and does not introduce cyanuric acid (CYA) or calcium into the water.

How long does it take shock to kill algae?

It takes approximately 3 to 4 days to kill algae by raising the chlorine level and maintaining it at a high level until all the algae is eliminated. It is important to run the filter continuously for 24 hours a day during this process.

How much bleach do I add to my pool to kill algae?

To prevent algae growth in your pool, you can add 6-12 cups of Clorox® Disinfecting Bleach per 5,000 gallons of water on an ongoing basis, in addition to regular chlorination.

Does hydrogen peroxide kill algae in swimming pools?

Hydrogen peroxide is indeed effective in killing algae in swimming pools. This powerful oxidizer surpasses the potency of chlorine. When hydrogen peroxide is exposed to sunlight, it eradicates the nutrients that bacteria and algae rely on for sustenance. Consequently, using hydrogen peroxide allows for the creation of a natural swimming pool that is devoid of chlorines, chloramines, and algaecides.

Is it safe to swim in a pool with algae on the bottom?

It is not safe to swim in a pool with algae on the bottom. Regardless of the severity, it is not recommended due to the potential health risks posed by the presence of harmful bacteria that thrive in significant amounts of swimming pool algae. These bacteria can lead to various infections, such as skin rashes, bacterial infections of the ears or eyes, and other health issues.

Is it dirt or algae in my pool?

The answer to the question “Is it dirt or algae in my pool?” can be stated as follows: Algae can develop in stagnant areas of the pool, where the water is not circulating properly. Mustard algae is capable of climbing the walls of the pool, unlike dirt which typically settles on the floor.

Similar Posts