Adding chlorine to swimming pools is crucial for safe, clean water, as it:

1. Kills harmful bacteria, viruses, preventing waterborne illnesses.

2. Stops algae growth, keeping pools clean and equipment unclogged.

3. Breaks down organic contaminants like sweat, avoiding cloudiness or odors.

4. Maintains water balance, ensuring clarity and reducing the need for frequent refills.

How Chlorine Works:

When chlorine is added to water, it forms hypochlorous acid (HOCl) and hypochlorite ions (OCl⁻), which are the active disinfecting agents. HOCl, in particular, is highly effective at penetrating microbial cells and neutralizing threats. Pool operators monitor "free chlorine" levels (typically 1–3 parts per million, ppm) to ensure there’s enough active chlorine to combat contaminants without causing skin/eye irritation.

In short, chlorine is a cost-effective, reliable solution that balances safety, cleanliness, and usability—making it indispensable for public and private swimming pools.