Which Is Better in a Pool or Spa: Chlorine or Bromine?

When it comes to sanitizing pools and spas, chlorine and bromine are the most commonly used chemicals worldwide. Both serve the primary function of eliminating harmful microorganisms from the water, but they differ in their application, interaction with water and skin, and overall effectiveness.

How Chlorine and Bromine Work

Chlorine is known for its rapid dissolving ability, which allows it to start disinfecting water almost immediately. It can be administered through in-line or offline feeders, floating dispensers, or directly in the skimmer basket, although the latter is generally not recommended. Granular chlorine, when pre-dissolved in a bucket of water, can be evenly distributed around the pool.

Bromine, on the other hand, works best when dissolved via a bromine feeder. As it sanitizes the water, it forms chemicals known as bromamides. Unlike chloramines (produced by chlorine), bromamides continue to disinfect without producing unpleasant odors or causing eye irritation. They can also be reactivated with shock treatments, making them a more persistent disinfectant compared to chloramines, which are simply removed from the water.

Chlorine vs. Bromine: Key Differences

Both chemicals are halogens and act as disinfectants, algicides, and oxidizers. Here are some of the key differences between them:

• Effectiveness: Chlorine acts quickly to eliminate pollutants but evaporates rapidly, limiting its duration of effectiveness. Bromine works more slowly but provides longer-lasting protection and helps maintain water chemistry balance due to its lower pH.
• Stability: Bromine is more stable than chlorine, especially in warm water, making it preferred for spas. However, both are susceptible to degradation by ultraviolet (UV) light, with bromine degrading slightly faster.
• Dosage: The required dosage of each chemical varies, with bromine generally requiring a higher amount to achieve the same level of sanitation as chlorine.
• Cost: Bromine is typically more expensive than chlorine, often costing up to twice as much, which can influence the choice of sanitizer in commercial applications.

Health and Safety Considerations

Both chlorine and bromine are safe for human use when applied according to manufacturer guidelines. However, individual sensitivities can lead to side effects:

• Chlorine can be harsh on the skin, eyes, and respiratory systems, potentially exacerbating conditions like asthma.
• Bromine is less irritating and produces fewer chemical odors, but it can leave a residual scent that some find difficult to eliminate.

It’s important for pool and spa operators to consider these factors when choosing between chlorine and bromine, especially if clients have sensitivities or allergic reactions to these chemicals. According to the Centers for Disease Control and Prevention (CDC), proper handling and storage of pool chemicals are essential to prevent accidents and ensure safe water quality (CDC, 2024).

Benefits of Joining the California Pool Association

The California Pool Association (CPA) supports independent pool service, repair, and maintenance business owners by providing resources such as general liability insurance, wholesale pricing on equipment, and a professional network. Membership in the CPA can enhance your business operations and provide significant cost savings.

For more information or to join, contact the California Pool Association, which offers extensive support and benefits to pool and spa business owners across the country.

This overview of chlorine and bromine highlights the importance of choosing the right sanitizer based on specific pool or spa needs, balancing effectiveness with cost and safety considerations. For further guidance on pool chemicals and their safe use, pool operators can consult industry resources and standards provided by organizations like the American Chemistry Council.