Chlorine

[G-money]

Can anybody explain to me the difference between the elemental chlorine found in saltwater and the chlorine found in tap water? What becomes of the chlorine in tap water when a synthetic salt mix is added to it? I assume there must be a multitude of ionic interactions rendering it much less toxic than it would be in a freshwater system. I am not speaking of chloramine, which I know is highly toxic and believe is relatively less reactive than chlorine.

The reason I ask is that I have debated that chlorine is less toxic to marine organisms because it is naturally present in seawater, while it is highly toxic to freshwater fishes because there is little to no Cl found in freshwater systems. Am I way off? I mean Cl ions are Cl ions aren't they?

[Randy Holmes-Farley]

The form of chlorine found in seawater is chloride (Cl-). Chloride is totally nontoxic, if such a thing can be said of any substance. It is half of table salt, sodium chloride. It is not reactive with most common chemicals.

The chlorine used in water supplies and swimming pools is diatomic chlorine (Cl2). It is reactive and toxic. That is why it is used in such applications: it kills things.

When mixed with seawater, it may degrade into a variety of things, but I'd expect many of them to be toxic too.

Consequently, I'd always advise removing chlorine from tap water somehow prior to use.