Chloramine

From The Aquarium Wiki

Chloramine (NH2Cl) is commonly used in low concentrations as a disinfectant in municipal water systems (your tap water) as an alternative to chlorination. This application is increasing in use. Chlorine (sometimes referred to as Free Chlorine) is being displaced by chloramine, which is much more stable and does not dissipate from the water before it reaches consumers. Chloramine also exhibits less tendency to convert organic materials into chlorocarbons such as chloroform and carbon tetrachloride.

Such compounds have been identified as carcinogens and in 1979 the U.S. EPA began regulating their levels in U.S. drinking water. Furthermore, water treated with chloramine lacks the distinct chlorine odour of the gaseous treatment and so has improved taste.

Chloramine in tap water gives a greenish cast to the water in bulk, versus the normally bluish cast to pure water or water containing only free chlorine disinfectant.

Tip - This greenish colour may be observed by filling a 5 US Gallons (18.9L) white polyethylene bucket with chloraminated tap water and comparing it to chloramine-free water such as distilled or RO water.

Untreated tap water with Chloramine in it when added to an aquarium tank in quantity will seriously damage or kill fish and other aquatic animals.

Chlorine is 69% of the chloramine molecule, ammonia is the other 31%.

1 Removing Chloramine from water
2 Testing for Chloramine
3 References
4 Links

[edit] Removing Chloramine from water

Running tap water through active carbon or Poly-filter for a couple of hours will break up this chemical into ammonia, Chloride and nitrogen. So you will need to add a water conditioner to remove the ammonia.

Some commercial chloramine treatments simply separate chloramine into ammonia and chlorine and remove the chlorine instead of neutralising both chemicals. This leaves free Ammonia in the water! These types are to be avoided as the ammonia will damage the gills of fish, reduce levels of dissolved oxygen and can cause an Algae bloom to start. Read the instructions on the bottle carefully!
See Water conditioners article for typical products.

[edit] Testing for Chloramine

There is no direct chemical method for measuring chloramine. Chloramine is indirectly estimated by calculating from the results of total and free chlorine. Since total chlorine is the sum of free chlorine and chloramine, the chloramine therefore is total chlorine less free chlorine.^[1]