Chlorine is the so-called “gold standard” of pool water types, known for its efficiency at killing bacteria. It counteracts contaminants in the water such as sweat, dirt, urine, and sunscreen or body lotions through a chemical reaction. Chlorine can be added once per week, using liquid, tablets or granular chlorine.

Chlorine is added to the water to kill germs. When chlorine is in a pool, it forms a weak acid called hypochlorous acid that kills bacteria like salmonella and E. coli, as well as germs that cause viruses such as diarrhea and swimmer's ear.

Pool chemicals are used to maintain swimming pools and spas to reduce germs and other microorganisms in the water and keep the pool looking clean. These products include sanitizers, algaecides, pH balancers, clarifiers, and shock. Pool chemicals are an important tool to protect the health of swimmers.