Chlorine

From The Aquarium Wiki

Chlorine (Cl) or Free Chlorine is a halogen chemical element.

In its free form, as added to water, it's in fact more correctly called dichlorine or Cl₂.

As the chloride ion, which is part of common salt and other compounds, it is abundant in nature and necessary to most forms of life, including humans.

It has a disagreeable suffocating odour and is poisonous.

Chlorine is an important chemical for some processes of water purification, in disinfectants, and in bleach as it is a powerful oxidant.

Chlorine is also used widely in the manufacture of many every-day items, or to purify water in various forms.

Used (in the form of hypochlorous acid) to kill bacteria and other microbes from drinking water supplies and swimming pools. However, in most non-commercial swimming pools chlorine itself is not used, but rather the mixture sodium hypochloride, a mixture of sodium and chlorine. Even small water supplies are now routinely chlorinated.

It is this use of Chlorine in tap water that brings it into contact with the Aquarium owner.

Due to Chlorine's nature, it is easily removed from tap water by simply letting the tap water sit in an open bucket for 24 hours and aerate it. Due to this easy method of removal, more water suppliers are switching to Chloramine to kill bacteria and microbes in our tap water.

Tap water that has chlorine in it has to be treated with a suitable water conditioner bottle to remove or neutralise this toxic chemical before being added to the aquarium otherwise it will kill your animals.

There are numerous water conditioners on the market, but due to the risk of your water supplier switching to using chloramine without notifying you, it is safer for your aquatic animals if you always use a water conditioner which removes chloramine as well.

Note there are some commercial bottles that simply split chloramine into ammonia and chlorine, then remove the chlorine. So there leave the ammonia behind! These products are probably best avoided.