Chlorine can be an effective chemical to use in keeping swimming pools clean, but its drawbacks — possible eye irritation, a strong smell, and the need for frequent monitoring of the pool water's pH level — leave some people searching for a chlorine alternative for pool disinfection. A number of substances can be used in swimming pools as a chlorine alternative, including bromine, a chemical similar to chlorine; and persulfates. Low-chlorine options include copper and silver, and polymeric biguanides. A chlorine alternative can provide many of the same benefits without some of the unwanted effects.
Bromine is chemically similar to chlorine and provides many of the same benefits, but it does not have the strong smell of chlorine. It can kill bacteria, help to break down and remove bather waste — skin flakes, oils and lotions — from pool water, and keep algae from growing. The best way to add bromine is usually by using a floating dispenser or a device called a brominator.
Persulfates, which also may be called active oxygen, also are a chlorine alternative. They can kill bacteria and bather waste but might not be effective against algae. Persulfates often are used instead of chlorine to shock a pool, because they are very effective at removing bather waste. Persulfates come in tablets or packets that dissolve the chemical in the pool water.
Polymeric biguanides are another type of chemical that can be used to disinfect swimming pools. They are usually best for use in a brand new pool that has not been previously treated with chlorine, because the two substances are incompatible and should not be used together. If polymeric biguanides will be used in an existing pool, all traces of chlorine need to be removed first.
Other substances use chlorine but in smaller amounts, which can decrease the negative effects of the chemical while retaining its benefits. Ozone, a chemical found in the air, may effectively kill bacteria in swimming pools. Because ozone can be highly toxic, it needs to be dispensed directly into the water to avoid releasing it into the air. A special ozone dispenser is attached to the pool’s plumbing, which only adds the chemical to the water inside of it and avoids dispensing ozone into the rest of the water. It may be necessary to also use small amounts of chlorine in pools treated with ozone.
Copper and silver are minerals that can be used to disinfect pool water using low levels of chlorine. This chlorine alternative provides many of the same functions, including prevention of algae growth. Silver needs to be added to the pool in the form of silver ions. To accomplish this, an electric-powered ionizer can be attached to the pool’s plumbing and may be used to dispense ions into the water.