Chlorine to Chloramines

Do pet fish owners need to be concerned about their water utility changing from chlorine to chloramines for drinking water disinfection?

reverse osmosis banner vertical

If you love your pet fish, you should use some vigilance concerning your aquarium's health, especially the chemicals in the water.

Unlike chlorine, chloramines cannot be removed by allowing the water to stand for a period of time or by boiling the water. Special chemicals must be added such as ascorbic acid to degrade the chloramines or the chloramines can be removed by using granular-activated carbon filtration.

Although most utilities that currently use chloramines for disinfection just started during recent years to reduce the formation of trihalo-chemicals as disinfection byproducts, some utilities have used chloramination since the 1920s.

Frequent weekly or bi-weekly water changes are an important part of keeping a fish tank healthy and stable. Over time waste products accumulate. And when water is lost to evaporation, the minerals and waste products are left behind, increasing their concentration over time. Also, the nitrification process (The filter converting ammonia into nitrite into nitrate) will slowly decrease the water's buffering capacity. If the buffering capacity is depleted, the pH can crash very quickly. Water changes help remove the bad stuff, and help replenish the tank water's buffering capacity. When adding tap water to a tank for water changes, several things should be done to make sure that you don't shock the fish.

First of all, the temperature of the replacement water should be close to the same temperature as the tank water. Second, and just as important: The water must be chemically safe for the fish. If you get your tap water from a commercial water system, that water is treated to make sure it's safe for human consumption. The water is cleaned and filtered. Then, chemicals are added to the water to prevent anything harmful from growing in the water while it's in the pipe leading to your home. Until recently, most water treatment facilities used Chlorine to kill off any organisms in the water. The small dose of chlorine is safe to drink, but many people notice the slight chlorine odor.

One problem water treatment plants have with chlorine is that it's unstable, and easily dissipated from the water. This means that the treatment plants need to put in higher levels of chlorine so that they can be sure that some will remain in the water when it reaches your home. Recently, water systems have started treating tap water with chloramine instead of chlorine. Chloramine is a combination of chlorine and ammonia. It's much more stable than chlorine. It won't dissipate from the water as easily, and it isn't as likely to combine with other chemicals. But, chloramine isn't as good at killing off the microorganisms in the water as chlorine, so higher levels of chloramine are often used.

Typically, water treatment plants use about 1 ppm of chloramine. All this hard work and chemistry is important to keep people healthy. But, the same chemicals which keep people safe can be VERY toxic to fish. Adding tap water with chlorine or chloramine to a tank can kill off fish quickly. It can also kill off the bio-filter bacteria that keep your tank healthy and happy. So, this water must be made safe for the fish and tank. How do we do this? There are several common approaches, and their effectiveness varies depending on whether your local water treatment plant uses chlorine or chloramine. If you don't know which your water system uses, ask them. If you don't know who your water supplier is, the American Water Works Association's List of Water Utility Home Pages can help. Most pet fish dealers are familiar with treatment methods for the removal of chloramines.

Reading next