Algae, a plant that grows in stagnant water, produces almost eighty percent of our atmosphere’s supply of oxygen. It grows in ponds, lakes, the ocean, and in pools, in turn becoming our most pressing inconvenience during the summer. We crave a dip in the cool pool water as the temperatures skyrocket, and we can’t do that when algae are present. It presents a significant health hazard to humans though not because of the plant itself; rather, the bacteria that breed on it is the danger.

Algae also can bring nuisances like mosquitos and other insects to our yards. Mosquitos can bring a variety of illnesses, like malaria, the West Nile Virus, Yellow Fever, the Zika Virus, and so many other deadly diseases.

Before addressing the issue, it is imperative to assess your situation and ask the following questions: What are algae in pool water treatment options? What type of algae is growing? What causes it? What steps can you take to prevent further or future infection? How can you get rid of your current algae problem? Though these are but a few questions, every list must start somewhere. Below you will find a small guide to help you formulate your plan.

Types of Pool Algae

Green Algae

This is the most common type. It floats freely and does not attach to anything, unlike other types of algae, such as Black algae. It is the most common type of algae because it feeds off of a human error. Every pool owner has a regime they follow to maintain their pool, and when your pool’s chemical balance is out of whack, or even lightly messed up, these algae jumps at the opportunity to infect your pool water. Commonly appearing after lightning storms, these algae can form because of the buildup of nitrogen that lightning causes. Algae feed off nitrogen and thus form often after storms.

Yellow or Mustard Algae

This algae in pools appear yellow, or closer to a mustard color because it lacks chlorophyll. Chlorophyll is the green pigment that plants make during photosynthesis, the process where plants convert sunshine, water, and carbon dioxide into food. These algae in pool water are tougher to spot as most people tend to believe that the growths are just dirt on their pool floors. They then think nothing of it, until it grows out of control and becomes an issue.

Black Algae

This strain of algae, by far, is the toughest to get rid of. The spores enter the water and begin as small dots, or long growths, in the water. It can look like dark dirt deposits. It anchors itself to the bottom and sides of your pool, making it necessary to scrub the gunk away. Though it’s named “black algae” it can also appear deep green or blue. Using algaecide might not work with this type of algae, due to the wax coating that covers the leaves of the plant. This coating makes the plant almost impervious to chemicals. There are special formulations of algaecide specific to killing black algae.

Causes of Algae Growth

As previously stated, algae can gain a foothold in your pool when your pool care regime is disrupted. Chemical imbalance almost entices the algae to take root in your pool. Spores can also infect your waters after lightning storms when nitrogen builds up in the air or water because lightning is made of nitrogen. If your pool filter is not working optimally, this can cause your pool water to become stagnant, meaning it has no circulation.

How to Treat Algae in Pool

After diagnosing your pool’s condition, figuring out what type of algae is growing, and planning your new regime, there are a dozen ways to get rid of the infestation. The best time to start trying to rid your water of algae is at the brightest, hottest time of the day. At this time, algae grow at its most rapid rate, meaning the treatments will be most effective then.

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  • Pool Shock: A chemical combination that literally “shocks” your pool water clean.
  • Algaecide: A concentrated algae killer, that works best when you pour it over where the algae began to grow. There are two types of algaecide: metal-based and ammonia-based. The ammonia-based algaecide is less expensive and will be less likely to stain your pool than the metallic (copper and silver based) algaecides. Using algaecide regularly helps keep your filter from becoming clogged with plant matter and debris, keeping your pool circulation optimal.
  • Chlorine: The go-to pool cleanser. It’s in every pool regime, and the government uses it to clean our drinking water. It cleanses water of microorganisms, bacteria, and other infectants, but can’t kill complex organisms like algae. This chemical comes in tablets, powder form, and in liquid form.
  • Bromine: Kills what chlorine cannot. Use this with chlorine to increase pool cleanliness as it supports chlorine by killing complex bacteria and microorganisms. It works better in warm water than chlorine, so you can also use it in Jacuzzis and spas.

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  • Filters: Your pool filter is its filtration system, like a human’s liver or kidneys. It filters through the water, pulling out “toxins” like bugs, algae, and debris, and moves the chemicals in your pool around to help spread them. Without good water circulation, your pool water will become stagnant, which also breeds algae. Your filter cleans your pool daily, taking the pressure off you and your family!
  • Skimmers: These handy nets can skim out dead insects, leaves, and large twigs that can interrupt your pool filters, pumps, and vacuums. They are inexpensive and come in a variety of sizes.
  • Pool Vacuum: An effective preventative to Black Algae. Since Black Algae anchors itself to the bottom of the pool, the vacuum helps to keep the bottom clean. It even adds to circulation, since the vacuum moves the water in the pool while it runs, keeping the water from becoming stagnant.
  • Pool Brush: Similar to a dish brush, the pool brush has bristles to scrape gunk from the sides of your pool. Black Algae has a tendency to latch onto the sides of your pool as well, so scrubbing the algae away is an effective removal method. It is also imperative that you scrub any tile that your pool might have because algae spores can hide in the grout of the tile as well as on the tile itself. The algae in pool tiles grow through the grout, and the roots help to deteriorate the tile. You might have to replace your tile if the algae cause significant damage.

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Replacement Parts

After an encounter with algae, particularly Black Algae, you might want to replace parts in your pool.

  • Pool Liners: Black Algae leeches onto your pool liner, anchoring it. This makes it difficult to get rid of, and if there is extensive damage to your pool liner, opt to get a replacement before next season.
  • Pool Ladders: Algae can ravage your pool ladder, making it slippery and even staining it. Consider replacing your ladder if you have a recurring algae problem because sometimes, they can retain spores.
  • Pool Toys: Everyone loves blow-up toys, but when algae attacks, it is best to throw the old ones away. They can retain spores of the algae, like the ladder, especially if the spores manage to seep through the inflation valve.

All in all, replacing certain items in or around your pool after an algae infestation is a good call.

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Nobody wants to have algae in pool water, especially their own, but when the problem does arise, hopefully, this small guide could help or guide you in the right direction. Note that pools need chemicals and filtration systems based on how much water they hold. The size of the filter and dosages of chemicals vary with pools, so it is best to know the amount of water your pool can hold when you shop for equipment.

Another place you can find help is on You can find a variety of tips on how to care for your pool there. The website has filters, nets, and other tools, like the variable speed pool pump, that you can use to fix your algae infestation and form your regular pool regime. Chemicals, equipment, and cleaning tools are often part of most regimes.

On, you can find dozens of articles with information on chemicals, winter care, types of pools, and even pool inspections for public pools. If your residential pool has an algae problem, whether it be visible algae or cloudy, unclean water, you should always report it. Algae in pool water breeds bacteria, which is unsafe for children and adults alike. There is more information about public pool permits, inspections, lifeguard regulations, and laws, on

Feel free to take a peek before you head to the store because they are likely to have the answers to your questions and the equipment you need to have a safe, happy summer!

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