Chlorine Evaporation

[djnrg]

Hi Everyone!

I'm just wondering how long it typically takes chlorine to evaporate out of tap water. For example, instead of always using a de-chlorinator, I leave milk jugs full of water out for about a week or so. Theres no agitation to the water, they are just full milk jugs that I let sit for a while.

Is this sufficient to let all the chlorine evaporate? How long does it usually take, and does the water need to be agitated to get all the chlorine out?

The reason I ask is that when I put the new water in the tank, I find that the fish start to twitch and swim weird, until I get worried and dump a bunch of dechlorinator in there.

Any tips?

Thanks!

-James

 

[SirMinion]

Unfortunately, simply leaving water to stand is no longer sufficient to remove the chemicals added by the water company.

In the past the chlorine they added would indeed evaporate if the water was exposed to air for a while, but now water companies are adding the more stable chloramine compounds to the water which do not evaporate and must be neutralised with water conditioner.

Water conditioner also binds metal salts in the water which could be harmful to your fish, including copper or even lead from your pipes, mercury from industrial processes and aluminium from the soil.

 

[modernhamlet]

Unfortunately, simply leaving water to stand is no longer sufficient to remove the chemicals added by the water company.

In the past the chlorine they added would indeed evaporate if the water was exposed to air for a while, but now water companies are adding the more stable chloramine compounds to the water which do not evaporate and must be neutralised with water conditioner.

Water conditioner also binds metal salts in the water which could be harmful to your fish, including copper or even lead from your pipes, mercury from industrial processes and aluminium from the soil.

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Well said, SirMinion. Not enough people know that.

 

[freddyk]

Even regular chlorine won't simply evaporate, it needs to be gassed out through aeration. Having milk jugs full of water just sitting there is accomplishing very little. The best thing for most aquarists these days is to simply add the water straight with out worrying about aging, and using a water conditioner (dechlorinator).

 

[Saz]

I didn't know that chlorine could evaporate from the water anyway. I bottle tap water and leave it to stand in the sun for a few days. The ultra violet light breaks up chlorine molecules into atoms. Does this work???
Then after leaving water to stand I add stress coat to condition the water before adding it to the tank anyway so my fish don't suffer the symptoms that chlorine causes.
Does this mean that leaving water to stand is just a waste of time?

 

[Dubby]

Here are a few Q&A from a US Dept of Utilities website that should help ..........


Q. Will letting water sit for a few days remove chlorine?

Yes. Unlike chloramines, which may take weeks to dissipate, chlorine will dissipate when water sits for a few days.

Q. Will a carbon filter remove chlorine?

Yes. However, to remove chloramines the filter must contain high quality granular activated carbon and you must allow sufficient contact time.


Q. Will a reverse osmosis process remove chlorine?

No. The permeable membranes can catch dissolved salts, but chlorine will pass through easily.

 

[Dorkhedeos]

i thought chlorine evaporated even if there wasnt any agitation. thats why people have to add chlorine to their swimming pool often even when its not in use