How To Get Rid of Algae In Your Pool Quickly

By Shiloh McGinley

August 25, 2022


How To Get Rid of Algae In Your Pool Quickly

How To Get Rid of Algae In Your Pool Quickly

Algae is every pool owner’s nightmare. Slimy, gross, and dangerous to the health, the formation of algae in your pool is often the result of an untreated imbalance in the pool’s chemistry. 

But not ensuring that all the chemicals are at an optimal level, your pool becomes a breeding ground for microbes which can then lay host to water bugs. Pool algae can also irritate the skin and compromise the immune system of those unfortunate to swim in a pool that has it. 

If you’re a pool owner who is dealing with algae growth though, don’t worry! There’s a perfectly easy solution to getting rid of pool algae and making sure it never comes back!

In this article, we’ll go over what algae are, what their different forms are, and how to get rid of them as quickly as possible. 

What is Algae?

In the most basic form, algae are nothing more than a type of plant that loves moisture. They love places that are constantly wet and have access to sunlight, making your swimming pool essentially prime real estate for these invasive plants. 

Algae begins growing usually as a result of low chlorine levels, poor filtration, poor water circulation, or a combination of all these factors. When the conditions are just right, pool algae can grow rapidly, sticking to the walls and floor of the pool and floating freely on pool surfaces. 

More than just being gross to touch and look at, algae can also host harmful bacteria like Salmonella and E. Coli. As such, swinging in algae-infested swimming pools can pose serious health risks to you and your family. 

Once algae get out of control, it can be hard to fully get it out. Even when you’ve scrubbed every inch to spotlessness, algae spores might still be floating on the water or embedded in the grooves of the tiles. This means you’ll have the same problem again eventually. 

Once you notice algae, even in small amounts, it is best to treat it immediately.

Types of Swimming Pool Algae:

Though there are many classifications of algae in the wild, swimming pool owners tend to experience usually one of the three common types of algae: Green, Black, and Yellow/Mustard Algae.

Green Algae

Green Swimming Pool

Green pool algae are by far the most common type of swimming pool algae. Green in appearance, you'll will notice this slimy substance growing along the walls of the pool or floating on the surface. 

Green algae and green water are relatively easy to scrub off though and a strong chlorine shock should be used to get rid of algae and eradicate them effectively. 

Black Algae

What Is Black Algae?

Of all the types of algae, this is probably the worst. More bacteria than actual algae, Black algae is a kind of mold that does not grow naturally out of a dirty pool. The spores occur naturally in natural bodies of water and cling to things like swim shorts or toys. Through these things, it is introduced to the pool where it slowly takes hold and grows.

Beginning as a few black spots, it quickly expands to cover much of the pool’s walls and floor.

Treating black algae early is essential because not doing so can cause structural harm to the pool itself. 

Black algae are capable of embedding themselves deep into the concrete and once it does this, it’s near impossible to even get rid of them without tearing out the tiles altogether. 

Mustard Algae (Yellow Algae)

Also known as yellow algae, this type of algae grows much slower than the other forms but is equally hard to deal with. An intensive amount of chlorine shock after a process of deep scrubbing is usually the only way to deal with this type of pool algae. 

Scrubbing before shocking is important because it gets most of the algae out and exposes the roots of the algae, allowing the chlorine to easily attack and kill it.  

5 SIMPLE Steps To Get Rid of Algae, Quickly

And now we arrive at the part where you learn to kill algae, so PLEASE be sure to pay extra attention. Although getting rid of pool algae quickly is not at all hard, it’s definitely going to take some patience and elbow grease. If you’re thorough with each of these steps though, you’re likely to have an algae-free pool in no time.

Step 1 - Check chemical levels

Swimming Pool Chemical Testing

The first and foremost thing you should do when dealing with algae is to learn why your swimming pool has algae in the first place. With a pool testing kit, check for the water’s pH level, alkalinity, chlorine level, and anything that might point to the cause of the pool algae.

You should also check if your swimming pool’s filter and pumps are running smoothly. Along with an imbalance of chemistry, a lack of circulation is also one of the likely culprits of pool algae growth. 

Once you have test results, make the necessary chemical adjustments with good-quality products. If your filters are faulty, give them a good clean or invest in more efficient ones. 

Step 2 - Clean and run the filters

Pool Pump & Filter

When cleaning your filters, depending on the type, you can either backwash or hose down the cartridge filter. You can also go one step beyond and use a swimming pool filter cleaning agent to scrub it down. 

The filter's job is to remove unwanted particles from the pool but algae can easily live on its surface too. In such cases, algae might simply creep back into the pool no matter how hard you scrub or shock. That’s why cleaning vigorously and regularly is essential. 

Once you’re positive that your filters are spotless, you can then proceed to run the filters and proceed to the next step.

Step 3 - Brush the 1st Time

Swimming Pool Brush

With either a telescopic swimming pool or a regular pool brush, it’s time to get a little labor intensive. Scrub deeply every inch of the pool's walls and floor and use a skimmer to skim the loose algae off the pool’s surface. 

Scrubbing manually provides two benefits. First, it gets a good chunk of the algae loose, making it easily filtered out or skimmed off using your swimming pool skimmer. Secondly, scrubbing exposes the roots of the algae, their more vulnerable layer. When you shock the pool with large amounts of chlorine, the exposed roots will be defenseless.  

If you’re dealing with black algae, you have to scrub extra hard and maybe use some chlorine tablets too. Black algae have several protective layers which makes it extra hard to dislodge from the pool’s structure.

Step 4 - Shock

How to Shock Your Pool

Shocking your pool is the process wherein you’re adding chlorine, or chlorine substitutes, to your pool to raise the free chlorine levels. High levels effectively kill algae as well as chloramines and other forms of bacteria. 

If you’re using liquid chlorine, the normal dosage might be around 1 gallon of shock per 10,000 gallons of water. 

Depending on the size of your pool, the amount of calcium hypochlorite may vary. Instructions on how to shock your pool should be on the chemical’s user manual or printed on the product itself. The filters should be on during this process to ensure that the chlorine is evenly distributed around the pool.

Take note that you should be wearing safety gear like goggles and gloves when doing this. Chlorine is known to irritate or in some cases burn the skin upon contact. 

Also, note that chlorine is highly photosensitive. The Sun’s rays might actually reduce the effectiveness of chlorine before it gets a chance to kill all the algae. That is why it is generally recommended that you shock your pool at night. 

Step 5 - Check chemical levels again

After 8-12 hours, you should be good to check the chemical levels again. After shocking a pool, the chemistry of your pool is likely to be imbalanced so you need to correct that according to the results of your pool testing kit. 

If you find that the chlorine levels are too low, then you might have to shock the pool again after 2 days. 

Step 6 - Use Algaecide

A full 24 hours after shocking your pool, you can use an algaecide. Usually in liquid form, pour it over the edges of your pool and let the filter pumps run, allowing it to circulate the pool for another full 24 hours.

Algaecide is a type of chemical biocide that kills algae by inhibiting photosynthesis or by rupturing their cell walls. Ideally, even when the algae are eradicated, you should be shocking your pool and using algaecide at least once a week to keep algae at bay.  

Step 7 - Brush for the 2nd Time

Even if you do not see any algae visible, that does not mean the coast is clear. This is especially true if you’re dealing with black algae. Scrub the walls and floor of your pool just as vigorously as you did the first time. Skim the surface of the pool of any debris, algae or otherwise, and ensure no nook and cranny goes untouched by the pool brush.

If you want to be extra certain, you can shock the pool again too. 

Step 8 - Use A Pool Vacuum For Algae

Swimming Pool Vacuum

Having scrubbed the pool, there’s likely to be a ton of floating particles. The filter alone cannot get all these things out. 

Next, you can optionally use a pool vacuum for Algae.  With the help of a pool vacuum, either robotic or manual, go through every inch of the floor and walls of the pool, picking up as much dirt and debris as you can. 

For a more detailed step-by-step process, read our post How to Vacuum A Swimming Pool.

However, many busy pool owners love using robotic pool cleaners for this stage as it saves a LOT of time and aches & pains in your back!

Dolphin Nautilus CC Plus Climing Walls

Not only does it help deal with algae effectively, but it also cleans your pool automatically without any need for supervision.

Getting a robotic pool cleaner is a great investment especially if you’re too busy for the rigors of pool maintenance.  I personally love the Dolphin Nautilus CC Plus (pictured above), and recommend it without hesitation.  

The Dolphin Nautilus CC Plus


Our #1 Recommendation

Check out the Dolphin Nautilus CC Plus, our #1 Recommended Robotic Pool Cleaner!

Step 9 - Clean and run the filters 

After all is said and done, the filters of your pool must be filled with tons of junk. Take the filters out and give them a good thorough cleaning. There are filter cleaning products that are fairly inexpensive which you can use to scrub your filters down. They can kill any algae that have attached themselves to the grooves, getting it pearly white with very little effort.

After that, run the filters again and enjoy a clean pool!

Algae Prevention

The old saying is that prevention is way better than treatment. If you’ve already dealt with algae, or simply want to know what you can do to avoid dealing with it, here are some preventative measures tips for you:

  • Maintain chemical balance. There are a lot of chemicals that go into making a clean and safe pool. With a simple pool testing kit and some inexpensive products, be sure to test your pool’s chemistry every other day and make the necessary adjustments. This is a great preventative measure, so don't be shy about doing this!
  • Use filters and vacuums regularly. With good quality filters and a reliable vacuum, your pool can deal with bacteria or algae-causing debris before they become a problem. Investing in these now can save you a lot of time and money in the long run.
  • Shock before or after large pool parties. The main introducer of contaminants to a pool is people themselves. Before or after throwing a large pool party, shock your pool and maintain optimal chemical levels. This kills any foreign contaminants and makes it a safe place for everyone to swim in.
  • Shock your pool at least once a week. Shocking your pool once a week, whether you see any algae or not, should be a regular maintenance practice for you. Better to err on the side of caution rather than spend another few hours of your life scrubbing.

Bottom Line on Algae in Swimming Pools

Algae is every pool owner’s worst nightmare. Even in small amounts, making sure you eradicate them completely can often be the cause of much anxiety. Nobody wants to swim in slimy waters after all!

That being said, they’re not unbeatable. By following these steps thoroughly, and engaging in some good old-fashioned scrubbing, you can get rid of algae quickly. And by taking the necessary steps to prevent algae, you are sure never to deal with it ever again.

Shiloh McGinley

About the author

Shiloh McGinley has been in and around swimming pools her whole life. She's seen a lot of products come and go, and she wants to share with you the best products that really work!

Shiloh is passionate about helping people stay safe in the water, and she loves educating others on how to choose the right pool products.

When she's not working, Shiloh enjoys spending time with her family and friends, and swimming - of course!

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