# sodium thiosulfate dechlor



## pandragon (Jul 10, 2014)

Hi all!

I just got some sodium thiosulfate crystals to use for dechlorination of free chlorine (NOT CHLORAMINE) and am trying to calculate amounts to make dechlor solution.

I read a few places saying 2 drops per gallon of 1% solution by weight (1gm sodium thiosulfate + 99 gm ro or distilled water) will take care of 1ppm chlorine. Does this sound about right? 

Half of the recipes I found used volume measurements, but the few that used weight measurements were all around 1% except for the ones for treating very large amounts where you wouldn't want to count drops or add gallons of solution.


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## Seattle_Aquarist (Mar 7, 2008)

pandragon said:


> Hi all!
> 
> I just got some sodium thiosulfate crystals to use for dechlorination of free chlorine (NOT CHLORAMINE) and am trying to calculate amounts to make dechlor solution.
> 
> ...


Hi pandragon,

I think you will find your answer in post #31 of this thread.


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## pandragon (Jul 10, 2014)

Gah I hate math! Anyways I figured that 4oz to gallon thing to be approximately a 3% solution...which is what I was asking for in first place, so that I could make smaller than gallon amounts....Although that doesn't tell me how much chlorine it will neutralize. It might be so strong that one drop will neutralize 4ppm chlorine, when I am trying to neutralize 1ppm and the solution might be too strong. Hmm I was really hoping I wouldn't have to get chlorine tests and trial and error figure out the proper solution for a given amount of chlorine.....

Thanks for the link.


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