Which of the following is vital for preventing pool algae growth?

Regular pool cleanings and chemical treatment are essential for preventing pool algae growth because they maintain the appropriate chemical balance and cleanliness of the water. Algae thrives in environments that are uncontrolled, particularly when there is an excess of organic material or imbalanced chemicals. By cleaning the pool regularly, debris and organic matter that can contribute to algae growth are removed.

Additionally, consistent chemical treatment ensures that the sanitizer levels—like chlorine or bromine—are sufficient to irritate or kill any potential algae spores before they establish themselves. Regular monitoring of pH levels also plays a crucial role, as pH imbalances can hinder the effectiveness of sanitizers.

In contrast, while a pool cover can help reduce debris input and may limit sunlight penetration (which algae use for photosynthesis), it is not a comprehensive solution on its own. Soaking the pool with chlorine weekly can help but may not be enough if the pool is not cleaned regularly or if the chemical balance isn't monitored. Turning off the filtration system can lead to stagnant water where algae can proliferate, making it counterproductive in the fight against algae growth.