Which of the following is a common sign of chlorine deficiency in pool water?

Chlorine deficiency in pool water can often be indicated by the presence of algae growth. Chlorine is a crucial sanitizer that helps to keep pool water clear and free of harmful microorganisms, including algae. When chlorine levels are insufficient, the sanitizer's ability to combat algae is compromised, allowing it to proliferate.

As algae thrive in low-chlorine environments, their growth can cause the water to appear cloudy or green, and may even lead to slippery surfaces around the pool. Monitoring and maintaining proper chlorine levels is essential to prevent such issues and ensure a clean and safe swimming environment.

While clear water, foamy surfaces, and strong chemical odors are also significant indicators of pool water quality, they do not specifically point to chlorine deficiency as directly as algae growth does.