Sodium Thiosulfate

cousinkenni

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May 18, 2005
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Hi Tom,

Here in Hawaii we have always had water that is relatively clorine free. That is all about to change with a new law that now requires its use in all drinking water. I have used Seachem prime in the past and although it is relatively inexpensive, when you have alot of fishtanks perofrm alot of wter changes it does add up. I have heard of a chemical that can supposedly neutralize bleach and remove chlorine (Sodium thiosulfate). I did a search on this forum and got back only two threads that mention it, but neither thread actually tells how it is used.

Can sodium thiosulfate be used to remove chlorine from tap water and if so how is it used? Would I have to make a stock solution first and then add 5mL or is it added dry?

Any information would be greatly appreciated.

Thanks,

Ken Takeuchi
 

Tom Barr

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Yes, that's what used for chlorine. But if they use chloramine, then you cannot use it.
Stick with Prime/Amquel etc.

It's not that much and if you want to reduce cost etc, run the tap through a carbon filter.

Regards,
Tom Barr
 

cousinkenni

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May 18, 2005
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I specifically asked the board of water supply what they will be using and they told me chlorine. I asked if they will be using Chloramines and they said no.

Carbon filters that attach to the tap aren't very efficient at removing chlorine/chloramine......unless you have the larger industrial size filters with lower flow rate, the contact time with the carbon just isn't long enough to do much at all.

When you have well over 100 tanks, a bottle of prime doesn't last very long and shipping to hawaii is very expensive. If there is a dry form that is relatively easy to use I would rather use that........especially if the chemical is relative inexpensive.

Thanks for the help.

Ken T.
 

Tom Barr

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Since it's definitely Cl, you can use a clear well, aeration etc to drive it off for a few hours first prior to use. 100 tanks is a lot and that would remove it also.
Sodium Thiosulfate should work fine.

Regards,
Tom Barr
 

cousinkenni

Prolific Poster
May 18, 2005
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Hi Tom,

Thank you very much for the response thus far. By any chance do you know the dosage of sodium thiosulfate (how much weight or volume/gallon)? I would prefer this method over having to aerate the water which would require a rather large container and a seperate pump. Although a clear well would most likely be cheaper in the long run I don't think it would be practical.

Thanks,

Ken T.
 

32103940

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May 12, 2012
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two things to note about that calculator:

1. it assumes you use hydrated sodium thiosulphate (crystal type) as opposed to the anhydrous form (powder type). the distinction is crucial...
2. calculations seem to indicate 1:1 stoichiometric ratio between thiosulphate anion and chlorine molecule (Cl2)

if i'm not wrong, the ratio should be 2:1..which means the calculator suggests to use only half the amount actually required to reduce the chlorine molecules.
 

Tom Barr

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Jan 23, 2005
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32103940;83444 said:
two things to note about that calculator:

1. it assumes you use hydrated sodium thiosulphate (crystal type) as opposed to the anhydrous form (powder type). the distinction is crucial...
2. calculations seem to indicate 1:1 stoichiometric ratio between thiosulphate anion and chlorine molecule (Cl2)

if i'm not wrong, the ratio should be 2:1..which means the calculator suggests to use only half the amount actually required to reduce the chlorine molecules.

This could be verified with a before and after test measuring free Cl.
As far as forms, I think the cheapest stuff is what is used(hydrated).

http://chlorine.americanchemistry.com/

Generally a 1% solution and adding 1/2 ml per 10 gal of tank water works. Or to be extra safe, 1 ml per 10 Gal.

I could be wrong too.
 
H

Htomassini

Guest
If you don't want to mess with it, magfloats labs makes a great dechlon and they sell it by the gallon. It is very concentrated. See if your local retailer carries it. The company is based out of fla and I use it.


Henry tomassini
www.theplantedaquariumstore.com
Sent from my iPad using Tapatalk HD
 

Biollante

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Jun 21, 2009
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Surprise, AZ
2:3, Na2S2O3: Distilled H2O, Like Me, Cheap, Easy & Ever So Effective

Hi,

40% sodium thiosulfate, distilled water solution, 1-drop ([SUP]1[/SUP]∕[SUB]20[/SUB]-ml) per gallon, chlorine or chloramine, cheap effective and no real problems with any residuals.
:calm:

During late spring and summer, if you live in hot and humid agricultural area perhaps a drop-and-a-half to two drops per gallon.
:)

Biollante
 

Anka

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Jun 5, 2012
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My only concern is that I currenlty use seachem prime which also binds heavy metals.

If I now switch to the Na2S2O3 then I will be missing out on that :(
 

Biollante

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Evil I May Be, But I Would Never Let You Do Without Metal Removal

Hi,

Sodium thiosulfate, Na[SUB]2[/SUB]S[SUB]2[/SUB]O[SUB]3[/SUB] removes metals, it is the reason it is/was used in old-timey photographic developing.:)

Sodium thiosulfate can also be used to help clear aquarium water.:cool:

Biollante