Pink algae are not really algae at all, but a form of bacteria. Commonly referred to as "pink slime", this type of swimming pool algae appears as reddish, pink spots or slimy streaks in corners and cervices, pipe-fittings and light fixtures on the water's surface which may slowly spread over an entire swimming area.

Pink algae will form slimy pink or clear layers over your swimming pool's surfaces. It typically appears in areas of the swimming pool that aren't exposed to direct sunlight, and that have little to no water movement.

Here are a few steps to take to help you get rid of those pesky pink algae:
  • Balance the chemicals. Be sure the pH, alkalinity and water hardness are at the correct levels.
  • Adjust the water’s pH to 7.0-7.2, the hardness to 150-250 ppm and the alkalinity to 80-100.
  • Bring the pink algae to the water’s surface by brushing the bottom, sides and steps of the pool.
  • Run the filter continuously and backwash twice per day until the water is clear again.
  • Shock your pool to kill off the algae. This entails raising the chlorine to 12ppm.
  • Continue brushing the walls, vacuuming the bottom of the pool, filtering and backwash to remove additional algae.
  • Once the chlorine level is town to 1.0-3.0ppm, it is safe to swim again.
It’s important to remember that correctly getting rid of any type of algae takes time. If the pink algae aren’t completely removed, there’s still a chance for it to continue to grow and spread. If a serious infestation occurs, it can turn the pool water cloudy or green, and if it won’t come off at all by brushing it, then you may have a more serious problem such as metal staining.

Algaecides and other anti-algae treatments are often useless against pink algae since the pink slime is caused by bacteria, not by true algae; however, there are formulas that will kill most types of bacteria, and specifically pink slime, which can be found at your local pool store.

Although it’s not entirely clear why pink algae is a reoccurring problem, we do know that it occurs outside of swimming pools as well; in fact, the growth of the bacteria can occasionally be seen in toilet bowls, sinks, and shower areas, so you pool owners aren’t alone! But one thing is clear: by properly maintaining the water chemistry, structure, and environment of your pool, you’ll have a better chance of avoiding pink algae in your swim area.