What can be used to detect small gaseous chlorine leaks in a chlorinator?

Using ammonia to detect small gaseous chlorine leaks is based on the chemical reaction that occurs when chlorine gas comes into contact with ammonia. When chlorine gas is present, it reacts with ammonia to form chloramines, which are a type of compound formed from chlorine and ammonia. This reaction is noticeable and can produce a distinct odor, allowing personnel to identify the presence of chlorine gas through the characteristic smell of chloramines.

In contrast, the other options do not serve as effective detection methods for chlorine leaks. Hypochlorite, lime, and soda ash do not exhibit the same chemical reaction with chlorine gas, and thus would not provide a reliable indication of its presence. They are more involved in the treatment and neutralization processes rather than detection. Therefore, ammonia remains the appropriate choice for identifying chlorine leaks in a chlorinator system due to the observable and detectable nature of the reaction it has with chlorine.