commonly used to disinfect public drinking water. When chlorine Cl
to water H2O, an acid known as hypochlorous acid (HOCl) is formed,
it will react with ammonia present in the water to form a very stable
compound known as chloramines: HOCl + NH3 =>NH2Cl + H2O
In some cities in USA and Canada, chloramines are used as an alternative
disinfectant to prevent the spread of waterborne diseases and to improve
the water quality. While chloramines are not harmful to humans, chloramines
have caused great concern among aquarists since chloramines are toxic
to both marine and freshwater fishes. Unlike chlorine which can be easily
removed, chloramines are more complex in its chemical bonding and chemically
However, when chloramines break down either naturally or through the
use of dechlorination chemicals e.g. antichlorine solution, ammonia is
released. This is again a toxic substance harmful to aquarium fishes.
While a cycled tank with its nitrosomonas and nitrobacter bacteria colonies
are able to convert harmful ammonia into less harmful nitrates, the sudden
rise in the concentration of ammonia in the water might prove too much
for the bacteria colonies to handle. The harmful effect of ammonia is
amplified when the pH of the water is high. This effect can be kept in
check by the use of pH control tools and a bag of zeolite rocks that
can remove ammonia from water.
||The use of zeolite to remove ammonia should be used only in times
of emergency e.g. ammonia spike since ammonia is a need for cultivation
of bacteria for nitrogen cycle.
Coping with chloramines:
1. use aged water to remove chlorine to prevent the formation of chloramines.
To prepare aged water, fill up a container with water and ensure sufficient
aeration is supplied to the water to create surface disturbances. The exchange
of gases caused by the disturbances will allow chlorine to diffuse out, lessening
the occurrences of chloramines. It is recommended that aeration is supplied
to the water for 24hrs or more for the complete removal of chlorine.
2. good maintenance of biological filter to ensure minimum level of ammonia.
This can be achieved by using good quality filter media or keeping flow rate
at an optimum level for bacteria to cultivate.
3. use of high quality activated carbon filter to remove chloramines.