With the turn of the seasons, sometimes pools can develop algae. Algae are simple plants that live in water and are capable of performing photosynthesis. While you may think algae are harmless, some types can be unsightly or even cause health problems. One particularly troublesome type of algae is mustard algae.

Mustard algae get its name from its color, which ranges from yellow to brown. It usually appears in patches and can be difficult to remove once it takes hold. In this article, we’ll give you tips on getting rid of mustard algae in your pool. Let’s get started.

How Do You Know If You Have Mustard Algae in Your Pool?

You likely have mustard algae if you notice a yellow or green tint to your pool water. This type of algae is often mistaken for common pool algae, but there are a few key differences.

  • For one, mustard algae tend to have a more distinct color, while common pool green algae may be more of a greenish-blue.
  • Mustard algae will often form in patches on your pool walls or floor. Common pool algae, on the other hand, tends to float in the water.
  • Mustard algae can also be more difficult to remove than common pool algae.
  • Also, cloudy or murky pool water is often a sign of algae overgrowth.

If you notice any of these symptoms, it’s important to take action immediately to get rid of the algae before it takes over your pool.

Is Mustard Algae Harmful to Humans?

While mustard algae aren’t harmful to humans, they can create a slip and fall hazard around your pool. If you have mustard algae in your pool, you’ll notice a yellowish-green tint to the water. The algae may also appear as clumps on the sides of the pool or the floor. Also, they’ll stick to the bottom and walls of the pool if you brush against them. Hence, a nuisance.

Mustard algae are most common in pools that don’t have a lot of chlorine. The algae can also take over if the pH levels in your pool are off. They are more common in outdoor pools because they’re able to grow in direct sunlight. However, they can also grow in indoor pools with windows or skylights.

Also Read: Best Bromine Pool Tablets

How To Prevent Mustard Algae from Growing?

The best defense against mustard algae is a good offense. You need to proactively attack the problem before it has a chance to get started. Here are some tips on how to do just that:

1) Test Your Water

It is best to catch an algae problem early on and nip it in the bud. Test strips are inexpensive and easy to use, so there’s no excuse not to do this regularly.

Use Health Metric 7-Way Pool and Spa Test Strips:

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To get reliable results, use a test strip that measures at least free chlorine, pH, and alkalinity. With these testing strips, you can easily and quickly test your water for a reliable and accurate reading. This allows you to enjoy your next swim without any stress. The strips are also faster and simpler to use than liquid testing kits and just as accurate.

This kit includes 50 pool test strips which will last 2-3 months, testing 2-3 times per week. Save time and money, and avoid hassle while knowing your water is balanced and safe with confidence. These seven tests provide extensive info for keeping your pool, spa, or hot tub crystal clear.

2) Shock Your Pool Weekly

Chlorine is the main weapon against all algae, so it’s important to keep your levels up. A weekly shock treatment will help ensure that your chlorine levels are high enough to fight off any algae that might be trying to take hold.

We recommend In The Swim Chlorine Pool Shock:

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It’s a powerful product that will quickly raise your chlorine levels and help kill any algae that might be starting to form. The product is designed specifically for shocking pools. It’s fast-acting and long-lasting, so you can be sure your pool is protected against mustard algae.

With the pool shock, you can easily and quickly eliminate mustard algae, bacteria, and other harmful contaminants from your pool water. This powerful chlorine shock treatment is perfect for regular maintenance, and it has a main active ingredient of 68% Calcium Hypochlorite (Cal-Hypo) for quick sanitizing. You should use 1 Pound per 10,000 gallons as a dosage. Also, follow the manufacturer’s instructions carefully when using this product.

3) Skim Your Pool

Skimming your pool is important for two reasons: it removes debris that can turn into mustard algae and helps circulate the water.

Use Betta 2:

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It’s a high-quality pool skimmer that will remove debris quickly and easily. It’s also designed to fit most pools, so you shouldn’t have any trouble finding one that works for your pool. The solar-powered Betta 2 is also environmentally friendly.

With the Betta 2, you no longer have to worry about mustard algae. This powerful and innovative pool cleaning device uses salt-chlorine tolerant motors to clean your pool quickly and easily. It comes with a large debris basket that can be removed for easy cleaning.

You can also use the wireless remote control function to switch between automatic and remote control easily. The special UV-resistant coating and material prevent damage caused by ultraviolet radiation emitted by the sun. The large debris basket with a handle and fine mesh filter makes removing debris easy without removing the cleaner from the pool. It also comes with a 1-year warranty. So give it a try today and see the difference for yourself!

4) Run Your Pump And Filter for 8 Hours Per Day

Filtration is key to keeping your pool water clean and mustard algae-free. By running your pump and filter for 8 hours per day, you can be sure that your water is being filtered properly and that any algae that might be present are being removed.

It’s also important to backwash your pool filter regularly to remove any build-up that might have occurred. By doing this, you can be sure that your filter is working at its best and that your pool water is as clean as possible.

Also Read: Best Pool Towel Rack To Buy

What is the Fastest Way to Get Rid of Mustard Algae?

You may have noticed some yellow or brown patches in your pool and are wondering what it is. This is most likely mustard algae and can be quite a nuisance.

Don’t worry, though; there are steps you can take to get rid of it quickly and ensure it doesn’t come back.

1. Disinfect All Pool Accessories

First of all, it’s important to disinfect all pool accessories. This includes floats, pool toys, and anything else that comes into contact with the water. You can do this by soaking them in a bleach solution for 10 minutes or using a pool-safe disinfectant.

Also, brush any areas where the mustard algae have been spotted. You want to remove as much of it as possible before treating the water.

2. Brush Your Pool

Once you’ve disinfected all the accessories, it’s time to brush your pool. This will help to loosen the mustard algae so it can be vacuumed more easily. Be sure to brush the entire pool, especially in areas where the mustard algae are most prevalent. Also, brush any areas where dirt and debris have accumulated.

3. Vacuum Out the Mustard Algae

After you’ve brushed the pool, it’s time to vacuum out the mustard algae. You’ll want to do this with a pool vacuum that’s specifically designed for algae removal. Be sure to vacuum the entire pool, including all nooks and crannies. Once you’re finished, empty the vacuum canister and dispose of the mustard algae properly. Also, be sure to brush the pool again to remove any remaining algae.

4. Test the pH Balance of Your Pool Water

Mustard algae can often signal that your pool water’s pH balance is off. So, it’s important to test the pH levels and adjust as needed. You can do this with a pool test kit or by sending a sample of your pool water to a lab.

The ideal pH level for pool water is between 7.2 and 7.6. If the pH level is too low, it can make the pool water more acidic and conducive to mustard algae growth. So, you may need to add some alkaline chemicals to raise the pH level. On the other hand, if the pH level is too high, it can make the pool water more basic and cause skin and eye irritation. In this case, you’ll need to add some chemicals to lower the pH level.

5. Brush Your Pool Again

After you’ve adjusted the pH levels of your pool water, it’s a good idea to brush the pool again. This will help to remove any remaining mustard algae and ensure that the new pH level is evenly distributed. Also, vacuum the pool again to remove any algae missed the first time.

6. Clean Your Filters

Another reason mustard algae may be thriving in your pool is dirty filters. So, it’s important to clean your filters regularly. You can do this by backwashing the filter or by using a chemical cleaner. Follow the manufacturer’s instructions for cleaning your particular type of filter.

7. Use Pool Shock

Pool shock is a powerful chlorine solution used to kill mustard algae. Be sure to follow the manufacturer’s instructions for using pool shock, as too much can damage your pool and make it unsafe to swim in. Also, be sure to brush the pool after using pool shock to remove any dead algae.

8. Brush Your Pool Again

After you’ve used pool shock, it’s a good idea to brush the pool again. This will help to remove any remaining mustard algae and ensure that the chlorine is evenly distributed. Also, vacuum the pool again to remove any algae that were missed the first time around.

9. Shock One More Time for Safety

For extra measure, you may want to shock your pool one more time. This will help kill any remaining mustard algae and ensure your pool is safe to swim in. Follow the directions on your pool shock product to properly shock your pool.

10. Test and Confirm Your Pool is Free of Mustard Algae

After shocking your pool, you will need to test the water to ensure it is safe to swim in. You should test for chlorine and pH levels. The chlorine level should be between 1 and 3 ppm, and the pH level should be between 7.2 and 7.6. If everything looks good, then your pool is ready to be used. You may want to shock your pool regularly to prevent mustard algae from returning.


Is It OK To Swim In A Pool With Algae?

You can swim in a pool with yellow algae, but it is not recommended. Algae can cause skin irritations and are difficult to remove from your body and swimsuit. Also, algae can deplete the oxygen in the water, which can be dangerous for swimmers.

How Does Mustard Algae Start?

Mustard algae are often introduced into pools through contaminated swimming pool water. It can also be introduced by wind and rain blowing pollen and other airborne contaminants into the pool. Once it’s in the pool, it multiplies quickly, especially in warm weather.

Does Mustard Algae Look Like Sand?

No, mustard algae do not look like sand. It is a greenish-yellow color and often has a slimy texture. It can form colonies on the walls and floor of your pool, as well as on bathing suits and other pool equipment.

Is It Mustard Algae Or Pollen?

The main difference between mustard algae and pollen is that pollen floats on the water’s surface, while mustard algae can sink to the bottom of the pool or stick to walls. However, both can cause skin irritations and other problems for swimmers. If you’re not sure whether you’re dealing with algae or pollen, it’s best to contact a professional pool service company for help.


Having read this guide, you now know how to eliminate mustard algae in your pool. You also know what causes it and how to prevent it from returning. Mustard algae is not a difficult problem to solve, but it is important to take action as soon as you see it. The longer you wait, the harder it will be to get rid of. Follow these steps, and you will have your pool looking sparkling clean in no time.

We hope that you found it helpful and informative. If you have any questions or comments, please feel free to reach out to us. We’d be more than happy to help you further in your journey to keeping your pool clean and clear.

Last Updated: November 20, 2022 / Categories: Outdoor & Garden, Pool & Spa / 10.6 min read / Tags: , /

About the Author: Kara Toomey

Kara Toomey

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