Why Use Bromine or Chlorine in a Spa?

Bromine and chlorine are effective water sanitizers.

Chlorine and bromine are naturally occurring elements that have sanitizing capabilities. This means they are able to kill organisms that can be harmful when present in swimming environments. If harmful pathogens are able to survive in the warm water of the spa, swimmers can be affected with numerous health conditions including rashes, skin infections and even respiratory ailments. It is important to use either chlorine or bromine in a spa to provide a safe swimming or soaking experience.

Pathogens

Bacteria, fungi and viruses inevitably find their way into the water of a spa. The Centers for Disease Control (CDC) lists cryptosporidium, Giardia, hot tub rash, legionella and swimmer's ear as the most common diseases transmitted by spas.

Sanitation

Sanitation involves killing organisms that can cause harm to people. Chlorine and bromine kill harmful pathogens by attacking their cellular membranes through oxidation. Once the cellular membranes are compromised, the interior components of the cells cannot function normally and the organisms perish. Chlorine and bromine are the most commonly used sanitizers for spas.

Oxidation

Oxidation involves the chemical removal of organic impurities. This organic material can include perspiration, body oils or bodily waste. Chlorine and bromine are able to oxidize organic impurities in the water and maintain the water's clarity.

Types

There are three main types of disinfectants used in spas, trichlor, dichlor and bromine. Trichlor (C3Cl3N3O3) and dichlor (C3HCl2N3O3) are chemical compounds containing chlorine that are in solid form. Bromine is combined with hydrogen and oxygen to form hypobromous acid, a solid that can be dissolved into the water.

Levels

In a spa, either chlorine or bromine can be used to accomplish the same goal: water cleanliness. The choice to use chlorine or bromine depends upon personal preference, as they are both equally effective. Chlorine and bromine should not be used at the same time. In a chlorine-maintained spa, free chlorine levels should be kept between 3 and 5 parts per million. In a bromine-maintained spa, bromine levels should be kept between 2 and 4 parts per million.

References

• Missouri Department of Health and Senior Services: Swimming Pool and Spa Water Chemistry (PDF)
• CDC: Health Swimming/Recreation Water: Illnesses
• Spa Depot: Hot Tub Sanitizer Comparison
• Columbus Public Health: Pool and Spa Safety (PDF)