Dealing with black algae (cyanobacteria)
The final classification of pool algae is “black algae.” As mentioned, black algae is not a genuine algae but rather cyanobacteria. It has a filamentous nature, anchoring themselves into the pool surface to establish growth. These filaments create challenges in releasing “black algae,” or cyanobacteria, from the pool surface for treatment. In addition to filamentous roots, cyanobacteria have a hard outer shell covering their layers of growth, making brushing an important part of the treatment process. Common consensus says cyanobacteria are more likely to thrive in areas of the pool surface that are rough or damaged, allowing them to take root. Based on the research conducted by the team, it revealed that cyanobacteria was most likely to grow in areas of the pool with poor circulation. Typically, cyanobacteria are often found in pool corners and on steps, areas characterized by poor circulation and conducive conditions for cyanobacteria to root and grow. This is one of the many reasons why routine pool brushing is an important part of weekly maintenance, regardless of whether any visible issues are present.
This research findings confirmed the presence of various naturally occurring algae types in pools. It is impossible to identify the exact type of algae growing in the pool just by looking at its colour in the water. The study demonstrated a mixture of different algae types in most of the collected samples, making it difficult for service professionals working poolside to discern the appropriate treatment required to effectively combat and prevent algae outbreaks.
While there is no silver bullet to keep in one’s toolbox to rely on exclusively, this research should encourage service professionals to consider a variety of approaches to treat different types of algae they might encounter in the field. Chlorine is a great algaecide and is effective against many types of algae found in pools. Typically, maintaining the standard sanitizer residuals is sufficient for preventing algae outbreaks. However, allowing this level to drop below the recommended range, even for a short period, can allow fast-growing algae to start spreading.
Once algae growth has started, it may require higher sanitizer levels to control them. Therefore, it is much more practical and cost-effective in the long term to consistently maintain the standard sanitizer level in the water. Chlorine’s primary job is to kill bacteria in the water, and the pool’s sanitizer is the sole chemical capable of doing so. While using chlorine to combat algae can be effective in most cases, it does use up a substantial amount of chlorine in the process, leaving less behind to kill bacteria. In contrast, other algaecides, such as quats, polyquats, or copper-based algaecides are solely dedicated to eradicating algae, ensuring chlorine remains available for bacteria control.
The research focused on finding an effective way to kill algae, independent of the sanitizer and without adverse effects such as foaming or staining. In general, the characteristics of algaecides indicate chlorine can be effective in many cases, but quats and polyquats are easier to help manage water chemistry. These positively charged molecules are drawn to the negatively charged cell walls of algae, acting like a magnet to bring the algaecide and algae cell together. Then, the quat or polyquat will tear open the algae cell wall, causing the algae cell to die.
Copper algaecides work differently by being ingested into the algae cell, effectively shutting down the internal processes and enzymatic reactions that keep the cell alive. Copper algaecides are highly effective against many algae species and are often among the fastest acting treatment options. Since most algae blooms in pool water are a mixed bag of algae species, it can be difficult to determine which algaecide will be the most effective. Consequently, some pools may not respond to traditional algae treatments or may require additional product doses to clear the water.
Although dealing with algae in pools can be frustrating, issues are not common if the water is properly maintained, and appropriate pool care procedures are followed. Maintaining a consistent sanitizer residual, weekly shocking, and regular application of an algae preventative treatment are key to preventing algae outbreaks. If problems do occur, using a strong algaecide along with chlorine-based shock treatment can help clear the water quickly and restore its clarity, making it suitable for swimming. Ultimately, while algae can be a problem, they can be effectively prevented through diligent pool care maintenance, ensuring a beautiful pool that is always ready for swimming.
Author
Alicia Stephens is the director of training and education for BioLab Inc. In her 23 years with the company, she has focused primarily on education, training, and development, as well as technical support and new product research and integration. Currently, Stephens supports all education and training initiatives for the BioLab Pro Dealer division.
