Safest way to remove bleach

[fishflorist]

No body replied this question in the bleach roch thread so I start a thread here.

For me , it's just about regenerating Purigen.

what is the most safe way to remove all the bleach after bath ? most bleach is base on sodium hypochlorite right ? which chemical is the best way to remove it ? except Prime or other commercial products.

And also I am using bleach to regenerate the Purigen. I am in the first experience of doing that. I use 100% bleach to regenerate (24 hours), and I cooked the bag in boilling RO water for about 20 minutes, then put it under sunshine (no sunshine all these days , sadlly ), for 7 days now. but I am still not sure about it.

I just want some chemical that can totally remove the sodium hypochlorite and or other possible chlorine or other poisonous things in bleach.

[NirvanaFan]

Any sunlight will kill bleach pretty quickly. Ever wonder why pools need a stabilizer for it? The cyanuric (sp?) acid stops the bleach from being burned off by sunlight.

[Habib]

A dilute solution of sodium thiosulfate should do the trick. :)

[Randy Holmes-Farley]

Sodium thiosulfate will break down bleach and chlorine.

[Randy Holmes-Farley]

I actually posted that 6 hours earlier than Habib, but since he is in Europe, his time stamp comes out the same. :D

[Habib]

Beat you! :D

[Habib]

And fishflorist is in China so he still has to come up with the question and post it. :D

[fishflorist]

Any sunlight will kill bleach pretty quickly. Ever wonder why pools need a stabilizer for it? The cyanuric (sp?) acid stops the bleach from being burned off by sunlight.

Thanks ! I heard of that before, that's one of my dechlorination procedure too.
only because the Purigen bag is quite small so that I'm not sure about every granule of Purigen can be exposed to sunlight, so I want some chemical to make sure of the dechlorination complete.

One of my friend did not do that well and the regenerated Purigen killed many corals in his tank, really scared me.

[fishflorist]

A dilute solution of sodium thiosulfate should do the trick. :)

Sodium thiosulfate will break down bleach and chlorine.

Many thanks to you both !!

and my I ask what dilution ratio will be good ?
? gram Sodium thiosulfate in ? ml sound good ?

And one more question, after soak in Sodium thiosulfate solution, I will need to rinse it several time, but still , there must be a little Sodium thiosulfate in the Purigen bag, is it completely safe for coral ?

[fishflorist]

I actually posted that 6 hours earlier than Habib, but since he is in Europe, his time stamp comes out the same. :D

you and Habib answered a question that I have not asked yet.... :hmm5:

[Randy Holmes-Farley]

I think if you rinse very well, concerns about thiofulate are minimal.

The concentration needed (or number of times new solution is needed) depends on how much bleach is present. Presumably you will rinse the bleach off, so probably not much.

here's a dechlorination recipe:

http://www.wchemical.com/SODIUM-THIOSULFATE-P51.aspx

from it:

For the neutralization of Chlorine solutions: - The amount of sodium thiosulfate required can vary with the pH of the water. A range of approximately 2 to 7 parts sodium thiosulfate to neutralize one part chlorine is generally suggested. To neutralize 1 liter of a 200 ppm chlorine solution, approximately 0.4 - 1.4 grams of sodium thiosulfate would be required. To neutralize one gallon of a 200 ppm chlorine solution, approximately 1.5 - 5.3 grams would be required. The use of a chlorine test kit is recommended.

[fishflorist]

so that's about 0.4-1.4g sodium thiosulfate to neutralize 0.2g chlorine.

I suppose after the rinse and sunshine, chlorine will be no more than 0.2g in the bag, so I use 2g sodium thiosulfate in 500ml (enough to soak the bag ) will be good enough.

after that, I rinse it with 1L RO water 3 times ,then it will be very safe to throw the bag into sump immediatley ?

2USD/500g sodium thiosulfate, use 250 times, 0.008USD once, cheap enough.

[fishflorist]

since I'v already started this thread, let's go deeper on this topic:

1, if there is no sunshine, put it in open air, until the whole bag go completely dry, is the bleach removed ?

2, is that UV in sunshine removing bleach ?

3, if I rinsed the bag, I put it under MH light (my tank have brace) until it go completely dry, is the bleach removed ?

4, suppose I have accidently added 10g sodium thiosulfate into my 200G system, what is the impact ? better explain it in chemical way ,but simple chemical way :lol2:

5, after bleach, if I put it into 1L RO water the boil it , keep boiling 10-20minutes, will that remove bleach completely ?

6, I am using a 200micro polyester bag(not the Seachem THE BAG), is polyester stable in boiling water ? will it release some chemical dangerous ?


7, still thinking :beer:

[Habib]

I will need to rinse it several time, but still , there must be a little Sodium thiosulfate in the Purigen bag

You can neutralize it with bleach :D

Joking aside, a few ppm thiosulfate should not do harm. Just give the bag enough time to exchange it wil clean water. Removing the bag several times from the clean water and putting it back will allow for a better exchange.

Residual thiosulfate can interfere with nitrate testing, giving false low values.

A company sold it many years ago as a nitrate remover. Fortunately they pulled it from the market.

[fishflorist]

You can neutralize it with bleach :D

Joking aside, a few ppm thiosulfate should not do harm. Just give the bag enough time to exchange it wil clean water. Removing the bag several times from the clean water and putting it back will allow for a better exchange.

Residual thiosulfate can interfere with nitrate testing, giving false low values.

A company sold it many years ago as a nitrate remover. Fortunately they pulled it from the market.

Thanks you Habib !

will the thiosulfate deplete in the tank soon ?

[Mike_Noren]

Ascorbic acid (a.k.a. vitamin C) neutralizes both chlorine/hypochlorite and chloramine. It's less efficient than thiosulphate so you need twice the dose, but it's non-toxic and easily available (sold in bags in the supermarket in the spice rack; it's used as a preservative).

I've never heard about sunlight removing chlorine and would like to read more about the mechanism, does anyone have a reference?

[fishflorist]

Ascorbic acid (a.k.a. vitamin C) neutralizes both chlorine/hypochlorite and chloramine. It's less efficient than thiosulphate so you need twice the dose, but it's non-toxic and easily available (sold in bags in the supermarket in the spice rack; it's used as a preservative).

I've never heard about sunlight removing chlorine and would like to read more about the mechanism, does anyone have a reference?

really ? I happen to have 100gram VC left (I was thinking use it as fish food soak or carbon source) and dont know where to use it.

[Habib]

Thanks you Habib !

will the thiosulfate deplete in the tank soon ?

Yes, as far as I recall it, it will be gone in hours / a day.

[Mike_Noren]

really ?
Oh yes (http://www.fs.fed.us/eng/pubs/pdf/05231301.pdf).

[fishflorist]

Yes, as far as I recall it, it will be gone in hours / a day.

That's great, thanks !

[fishflorist]

Oh yes (http://www.fs.fed.us/eng/pubs/pdf/05231301.pdf).

thank for your link !

I'll spend some time to read it carefully.