# Chlorine(Cl) in water

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Hey,

I have heard that removal of Cl2 can be removed from water by allowing it to sit for 12 hours or more. I was wondering how this works. I have set it up and was also wondering if anyone knows of any technique to detect Cl in liquids.

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Silver Nitrate is the standard test for Chlorine.

and Im not sure about leaving it to stand for 12 hours and how efficient that is, but it is practiced by people who keep fish in tanks.

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Silver Nitrate is the standard test for Chlorine.

and Im not sure about leaving it to stand for 12 hours and how efficient that is, but it is practiced by people who keep fish in tanks.

Yeah that is the purpose im testing it for.

I guess it could be it reacting with the UV light.

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well the silver Nitrate test is Incredibly sensitive, if theres ANY trace of Chlorine in there, it Will show

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Did you try thiosulfate or bisulfite to reduce chlorine and chloramines in into chloride?

This is also used by brewers to treat brewing water because chlorine can otherwise form extremely potent flavour active chlorophenols that are detectable as chlorine/plastic/phenolic flavours at the ppb range.

/Fredrik

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sodium thiosulphate is the standard way to de-chlorinate yes, BUT, the products left may not be good for the fish either, thats why I never mentioned it.

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sodium thiosulphate is the standard way to de-chlorinate yes, BUT, the products left may not be good for the fish either, thats why I never mentioned it.

yeah i thought of the sodium thiosulphate as well but came to the same conclusion as YT2095.

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Actually, to be a bit more specific, silver nitrate reacts with chloride rather than chlorine. Since Cl2 dissociates in water to give chloride it is true to say that silver nitrate will give a ppt with a solution of chlorine. On the other hand, if you wait a while for the chlorine to difuse out of the water (or better yet, bubble air through it) then test with silver nitrate you will still get a ppt. It won't tell you if the chlorine has gone. It would, for example give a really strong positive test with seawater but that has essentially no free chlorine.

Measuring free chlorine is a bit more tricky I think there are kits to do this; sold to aquarium owners.

If I wanted to dechlorinate water for an aquarium I'd probably just put pondweed of some sort in it and wait for a day or so. The plants might take a bit of a hammering but it would save the fish.

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sodium thiosulphate is the standard way to de-chlorinate yes, BUT, the products left may not be good for the fish either, thats why I never mentioned it.

Agreed, however the #1 dechlorinator for fish tanks in the US is a product made by API called Stress Coat. It contains:

1-10% Aloes, etract

1-10% Sodium Thiosulfate

>80% Water

Joe

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Water can be dechlorinated in a way that is good for fish, according to a site I was just looking at. ( http://www.vita-d-chlor.com ) They sell ascorbic acid, (pure vitamin C) and sodium ascorbate for that purpose.

I live in Melbourne, Australia, where low water levels in the reservoirs seem to be leading to an increased concentration of chlorine in the water supply. A Plastic bath-hose has acquired a thick coating of blue-green stuff inside, and the water smells like a swimming pool. For a few years now I've been adding a little ascorbic acid to the drinking water because it improves the taste, but only today, idly web-browsing, did I find the vita-d-chlor site and discover why.

I have a question regarding water testing that perhaps people here can answer. What is the difference between total chlorine and free chlorine in water, and what effect do they have on water quality?

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