According to the Western Australia Department of Health, the safe chlorine level for an outdoor pool depends on the temperature. If the water temperature is less than 26oC, chlorine level must be at least 2.0 mg/L; otherwise, it’s 3.0 mg/L. The ideal levels are lower in indoor pools.
To determine the level of chlorine in their pool, owners may use test strips. Like litmus paper, the strips change colour when dipped in an acidic or basic substance. Most test kits provide a colour scale users can refer to for a somewhat accurate reading.