Chlorine & Chloromine Koi Sturgeon Pond

In addition to dissolved compounds and organic molecules, natural fresh water also contains a wide range of microscopic living organisms, from tiny larve and protozoans to bacteria and viruses. The majority of these are non pathogenic, but some can cause can cause disease in both humans and animals. To render such waters for human consumption water companies treat it with suitable dissinfectants, the most common and widely used is chlorine. This is forced into the water as a gas and combines chemically with water to form, amoung other compounds, hypochlorous acid, which acts as the disinfectant.
A small amount of the chlorine remains as "free chlorine" and is relatively unstable in water by which means it can be and readilly dissuses into air. These added amounts of chlorine to water is of course safe for humans however can be fatal to our fish with the first signs being respiratory distress. The toxicity levels of chlorine toxicity to our fish is not only dependant on the amount contained within the water but is also effected by the waters PH value, oxygen content and the waters temperature.
With these facts in mind it is advised that you test your mains water remembering that in summer water companies increase the amount of chlorine as the warmer water harbours an increase in pathogenic bacteria, this will of course change the way we do our water changes during the summer to protect our fish from the higher toxicity of the increased chlorine levels. To aid the diffusion of chlorine bearing in mind it is an unstable compound in water, a fine spray from the hose can be used when topping up the pond, this will allow more of the water to be in contact with the air to which cholorine is dispersed.

Another addition to chlorine is the use of chloramines for disinfection of the water. Chloramines are complex organic derivatives of chlorine, they are formed from the combination of chlorine and ammonia. Chloramines are particularly effective because they are more stable than chlorine by means that they release twice as much hypochlorous acid over a longer period. Chloramines can also form naturally when chlorinated water mixes with nitrogenous compounds such as nitrate fertilizers. The problem to all fish keepers is that chloramines are difficult to erradicate and when starting a new pond, it is reccomended that you allow the whole system of filters and air pumps to run for at least 14 days before even considering adding any fish.