In a swimming pool or spa, algae are those green, brown, yellow, black, or pinkish slime that resemble fur growing on the steps and in corners — places where circulation may not be optimum. The majority of swimming pools are exposed to several hours of sunlight per day, and it’s sunlight that will speed up algae growth. If you notice an increase in algae growth, run the pump more often. Also keep the water balanced, which means more frequent testing. It may seem obvious, but remove things from the pool, such as floats, inflatable toys, leaves, and grass. Make a real effort to keep it clean. The following algae colors are described and remedies are recommended in The Ultimate Guide to Pool Maintenance by Terry Tamminen. Here’s how to identify and get rid of certain types of pool algae. 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 swim season is key to staying on top of a green algae outbreak. 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 mustard algae. Why? Unlike green or yellow, black algae doesn’t have that outer layer of slime, which acts as a protective barrier for the algae underneath. Black algae will penetrate deeply into hard surfaces, like plaster and concrete. It first appears as black spots and then proliferates. If you see signs of it, immediately use a stainless steel brush, which cracks the algae’s shell and allows sanitizers to penetrate it. Blue-green algae were formerly known as cyanobacteria, a blue photosynthetic bacteria that live in water or damp soil.
