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Can You Swim in a Pool With Algae?

Algae can stain, corrode, and wear your pool down. While you might want to swim in the pool on a hot summer day, an algae bloom might make you think otherwise. Algae is covered in dangerous bacteria, which leads many swimmers away from their pool. But is there anything you should worry about?

You can’t swim in a pool with algae due to the high bacterial concentration. This bacteria can cause itchiness, rashes, nausea, and many other unwanted side effects. Algae blooms can also stain your hair and clothes. If you dive into a pool with algae, dry off and take a shower right after.

In this article, I’ll explain why green algae is bad for swimming, what happens if you ignore the precautions, and how you can remove the algae before diving into the pool.

Is Green Algae in Pools Harmful to Swim In?

Green algae in pools is harmful to swim in because it’s filled with hazardous bacteria. You can inhale the spores on top of the water because they’re so small. Green algae can get on your clothes and cause long-term irritation if it’s not removed. Never swim in a pool unless it’s clean and clear.

Algae starts in small blooms. If your pool has a light green tint, it’s likely the start of a new bloom. Look for additional signs of algae growth, including cloudiness, brown spots, dark patches around the liner or gunite, etc. You can brush small algae blooms to push them towards the skimmer basket and pool filter.

What Happens if You Swim in a Green Pool?

If you swim in a green pool, there’s a chance you could develop a rash, sensitive skin, discomfort, and more. Green pools harbor lots of dangerous bacteria that’s unhealthy for you, your pets, and the pool water. Always get rid of algae blooms before swimming in the pool.

Here’s what you should know about swimming in a green pool:

  • Some green pools are discolored because there’s too much copper. Copper is often used to remove and prevent algae. However, excessive amounts of copper in the water can discolor your pool, clothes, and hair. It can also cause itchiness and lead to corrosion in your pool’s heater.
  • Green lights and some chemicals can change the pool’s color. Algae isn’t always the reason your pool is green. If your chlorine is around 4ppm, it’s unlikely that there will be enough algae in the pool to discolor the water. Remember to thoroughly dilute the chemicals and circulate them for a couple of hours.
  • Brushing green algae will turn the pool a light green shade. I always recommend pool owners brush the algae blooms because it makes them easier to push into the pool filter. It also helps chlorine and other algaecides get rid of the algae in the water. You can use a vacuum, too.
  • Algae can be brown, pink, black, and yellow. While green algae is the most common color in swimming pools, all algae colors should be treated with caution. Algae is dangerous for swimming. Remove the algae before jumping into the pool, and don’t forget to get rid of the cloudy dead blooms.

If you’re worried about swimming in a green pool or a swimming pool with algae blooms around the edges, read on for a simple removal solution.

How Do You Clean Pool Algae for Swimming Safety?

To clean pool algae for swimming safety, follow these instructions:

  1. Turn on the pool pump and add chlorine shock. Make sure you don’t add too much shock because it can saturate the water. Check the manufacturer’s recommendations for exact measurements. Pool shock instantly spikes the chlorine to neutralize algae blooms and clean the water.
  2. Use an algaecide to prevent additional algae growth. Copper-based algaecides naturally prevent algae from coming back after you remove the initial bloom. You can also use algaecides that collect fine debris and send it to the bottom of the swimming pool. Vacuum these clumps to get rid of the algae.
  3. Circulate the water until it looks white and cloudy. All pool chemicals require adequate pump circulation. I recommend running the pool pump the entire time you’re clearing the water. However, you can stick with anything over eight hours per day if you don’t want to use too much electricity.
  4. Use a water clarifier. Robarb Super Blue Water Clarifier increases your filter’s micron density. This chemical collects more debris than sand, cartridges, and DE. Clean the filter after the water looks clear to improve the pump’s gallons per minute. Each bottle can treat up to 160,000 of water.
Robarb Super Blue Water Clarifier

Algae blooms are much less likely to appear if you keep the pool between 2ppm to 5ppm. Don’t forget to maintain the alkalinity, pH, and phosphates to keep your pool algae-free. Optimal pump schedules prevent algae from growing, too. Run your pump for one hour per 10 degrees Fahrenheit outside.

Is It Safe to Swim in a Pool With Dead Algae?

It’s not safe to swim in a pool with dead algae because it can harbor bacteria. Dead algae release phosphates and nitrates that promote algae growth. It’s important to remove the dead algae before swimming in the pool. Dead algae typically looks white, cloudy, and dull compared to vibrant green algae.

Dead algae can be as dangerous as living algae because it’s harder to spot. Most dead algae blooms look gray, white, or cloudy. They blend in with the water, making them seem like there’s no issue.

If you think there’s dead algae in your swimming pool, I suggest getting rid of it as quickly as possible. Never swim in a pool with living or dead algae. Remove the dead algae with water clarifiers, and spike the chlorine to prevent it from coming back.

Despite its name, dead algae has living bacteria. These bacteria can grow more algae. It’s best to remove the dead algae right when you get rid of the living green algae blooms.


  • Jonah Ryan

    Jonah has worked for several years in the swimming pool industry installing and repairing equipment, treating pools with chemicals, and fixing damaged liners. He also has plumbing and electrical experience with air conditioning, ceiling fans, boilers, and more. When he's not writing for Temperature Master, he's usually writing for his own websites, and

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