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If you can think back to your science class you may recall that algae are one-celled plants. And if you happen to be an alga, you are not alone: there are more than 20,000 varieties.
In a swimming pool or spa, algae is that green, brown, yellow, black or pinkish slime that resembles fur growing on the steps and in corners, places where circulation may not be optimum. The majority of swimming pools are in the sun several hours per day, and it is sunlight that will speed up algae growth.
Green Algae
Also known as chlorophyta, is a slimy substance that can be found on pool and spa surfaces. First signs of it appear in small clusters on pool steps or lurking in corners. It’s at this stage that you should start to attack it. Green algae can grow quickly in 24 hours or less.
How to Treat: Brushing will remove green algae, but it won’t destroy it. Superchlorination—aka shocking or shock treatment—will sanitize pool water that might be resistant to normal chlorination. Maintaining your pool regularly during.
Yellow Algae
Also goes by the appetizing term “mustard algae,” because of its brownish or muddy yellow color. While yellow algae (phaeophyta) doesn’t spread as quickly as green algae, it is harder to destroy.
How to Treat: Like green algae, yellow algae grows in the same fur or mold-like pattern. Unlike green algae, brushing will not do much to remove it, although it will remove the top layer of slime, which exposes the algae underneath. Superchlorination and regular maintenance will help kill.
Black and Blue-Green Algae
Primarily found in lakes and ponds, it does find a home in unmaintained pools. According to author Tamminen, black algae is “the pool technician’s worst nightmare.” He continues, “at the first sign of black algae, you need to consider the pool or spa as a patient in critical condition.”
Why? Unlike green or yellow, black algae doesn’t have that outer layer of slime, which acts as a protective barrier for the algae.
How to Treat: As with any type of algae it’s best to first have your pool water analyzed to make sure it is properly balanced. Prior to and during treatment, the algae must be thoroughly brushed to “break open” the slime layer. Failure to do this critical step will prevent the algae treatment from working. Shock the pool very aggressively and continue to brush the black algae.
Pink Algae
A bacteria, appears as a reddish-orangeish slime, usually at a swimming pool’s water line. It is also attracted to PVC surfaces in a pool, especially piping. It seems to keep company with white water mold, which is a fungus. Of all its colorful cousins, pink algae are the easiest to maintain.
How to Treat: Simple brushing and regular sanitizing should keep it under control. If it has gotten out of hand, remove it, then shock it with a calcium hypochlorite shock.
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