Sodium Thiosulfate, Disodium EDTA, Sodium Carbonate Polyvinylpyrollidones

Zagreus

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I need to bleach a quarantine tank and turn it into a fresh clean hospital tank that has a nasty Uronema Parasite. I am following HumbleFish tank sterilization and reseeding protocol https://humble.fish/community/index.php?threads/sterilize-reseed-any-tank.938/

After raising the tanks chlorine to 100 ppm the remedy calls to run the tank for 48 hours to sterilize and to dissipate some of the chlorine out followed by a dosing of Sodium Thiosulfate to neutralize the balance of the chlorine.

The issue is the only Sodium Thiosulfate I could find was mixed with other products which are said to reduce metals and the % or concentration strength is not listed. Here is the listing of other chemicals Disodium EDTA, Sodium Carbonate Polyvinylpyrollidones.

However, the Aqueon Water Conditioner Bottle says add 5ml per 10 gallons of tank water to neutralize chlorine and metals found in typical tap water. I read somewhere that typical tap water is around 4ppm chlorine or less. So with 4ppm water at 40 gallons I would need 20ml of solution. For 100ppm tank chlorine / 4ppm typical tap water chlorine I would need 25 doses of 20ml of solution or 500ml of total solution. The bottle has 473 ml of solution so I would need to drop the whole bottle in. Apparently after another 48 hours after dosing Sodium Thiosulfate et all and 96 hours after initially dosing bleach, the water is claimed to be safe and conditioned for fish.

I have no idea how this works or if the Disodium EDTA, Sodium Carbonate Polyvinylpyrollidones also breaks down and or neutralize into something non-toxic to fish. However, I would like a review of my logic to see if this makes sence now as a solution to bleach, sterilize, neutralize chlorine toxicity and add new seed life back to the tank. Remember I am trying to use and save my tank water instead of completely trying to drain it out, drying it completely everywhere, flushing it and then refilling it to kill the Uronema Parasite.

Thank you,

Zag-
 

Randy Holmes-Farley

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Why not just buy sodium thiosulfate? Many places sell it, including amazon.

I would not want a lot of EDTA in the tank, if you can avoid it, as it will impact the bioavailability of trace elements. But if there is no alternative, it may not be a big problem.
 
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Zagreus

Zagreus

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Why not just buy sodium thiosulfate? Many places sell it, including amazon.

I would not want a lot of EDTA in the tank, if you can avoid it, as it will impact the bioavailability of trace elements. But if there is no alternative, it may not be a big problem.
Thank you Randy! I found sodium thiosulfate at pinch a penny pool supply but in powder but again strength not labeled. I will keep digging. This will be for a fish QT Hospital tank only. But if EDTA has a long life i don't want it the tank either because who knows down the road. Thank you as usual!
 
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Zagreus

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Oh, for a fish QT tank, a little EDTA is not a problem.
Thank you, I feel a little foolish asking this but after i sterilize, neutralize the chlorine, I plan to reseed the tank with nitrifying bacteria for about a week and then will begin ramping up copper to 1 ppm before i start adding fish to a 30 QT. What is the half-life of Disodium EDTA in saltwater and will it begone by the time i start adding copper back in. Otherwise i just found some Sodium Thiosulfate, Fine Crystals, 99.5% min, 500 Grams that i can order instead of using this Aqueon Water Conditioner with EDTA?
 

Randy Holmes-Farley

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I'm a little reluctant to advise much as I've never really heard of someone sterilizing the tank and wanting to actually use the water that was sterilizing the tank. I'm not certain if thiosulfate actually removes all the toxic compounds that form with chlorination of seawater. It may, but I do not know.

Why not toss the old water? Sterilize with tap water. then add new seawater?

The EDTA doesn't have a "half life" that I could quite. It will likely only break down when hit by UV. It will still be there when you add copper.
 
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Zagreus

Zagreus

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I'm a little reluctant to advise much as I've never really heard of someone sterilizing the tank and wanting to actually use the water that was sterilizing the tank. I'm not certain if thiosulfate actually removes all the toxic compounds that form with chlorination of seawater. It may, but I do not know.

Why not toss the old water? Sterilize with tap water. then add new seawater?

The EDTA doesn't have a "half life" that I could quite. It will likely only break down when hit by UV. It will still be there when you add copper.
Thank you...you just saved me some headaches. I know this sounds crazy. I actually have a RODI system and can connect a temporary float valve to refill the tank. I wat trying to do this https://humble.fish/community/index.php?threads/sterilize-reseed-any-tank.938/ but am thinking it is more headache than its worth and to dump the water and start over with clean RODI water and new salt. Thanks, Zag
 

Randy Holmes-Farley

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Thank you...you just saved me some headaches. I know this sounds crazy. I actually have a RODI system and can connect a temporary float valve to refill the tank. I wat trying to do this https://humble.fish/community/index.php?threads/sterilize-reseed-any-tank.938/ but am thinking it is more headache than its worth and to dump the water and start over with clean RODI water and new salt. Thanks, Zag

That sounds like a better plan to me. I'm not sure Humblefish has thought through the chemistry of adding chlorinating agents to seawater.
 

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"Sterilizing" ocean water at between 5 and 25 ppm chlorine seems to be the sweat spot... There have been reports of trouble using SW that has been chlorinated bellow or above that range. My experience and the following information is based on delicate larval SW fish, not coral tanks... Anyway, I've had good success chlorinating ocean water to 5-10 ppm chlorine for 12-24 hours, before dechlorinating and using that water as my exclusive source of SW in my system for 5 years (per Martine Moe method, pg 49,50 in his newest "Marine Aquarium Handbook"... but also in the older additions). ... chlorine measured on a pool chlorine (OTO) test kit.... (which may not be accurate chlorine levels when used with salt water, but that is how the method works). Apparently, at least 5 ppm Cl levels are needed to "burn up" the organics in the water to an adequate level and reduce residuals, but beyond 25 ppm things can get wonky... In a Hawaiian Dwarf angelfish breeding trial they experimented with raising ocean water to 60ppm Chlorine for 24 hours with negative effects on spawning, and then lowered to 25 ppm for 24 hours, also resulting in poor spawning success until they settled for 25 ppm, but for no longer than half an hour with good success. At the moment I can only find the abstract for the paper on the internet:


The paper mentions that residual bromine compounds have been the biggest concern with chlorination, but otherwise it is not well studied what is actually going on at a chemical level.

Years ago I heard that Artificial Sea water salt has reduced bromine so that it can be used with ozone (and less danger with chlorination). But I'm not sure if that was true or if it is still the case.
 

Randy Holmes-Farley

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Years ago I heard that Artificial Sea water salt has reduced bromine so that it can be used with ozone (and less danger with chlorination). But I'm not sure if that was true or if it is still the case.

It was true for some mixes, but is no longer true.
 

Jilba J

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Why not just buy sodium thiosulfate? Many places sell it, including amazon.

I would not want a lot of EDTA in the tank, if you can avoid it, as it will impact the bioavailability of trace elements. But if there is no alternative, it may not be a big problem.
Hi ,
i have used de-chlorinator in my freshwater tanks that mentioned it has (sodium thiosulphate and disodium EDTA) but it didn't mention the percentages it was included. however now i purchased Sodium thiosulphate crystals from a LFS, and the municipal water that im using for tanks are bit cloudy is it safe for me to add Disodium EDTA with water changes ? and how much EDTA should i add? can i just mix some in tank water and add the solution directly to the tank with water changes ? will the EDTA harm my fish and the biological filter bacteria?
 

Jilba J

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The purpose of your adding EDTA is to reduce possible metal toxicity?
Yes, the municipal water parameters are way off normal these days, is there a fish/ beneficial bacterial/plant safe dose of EDTA available that we can add without any risk? like X number of mg for Liters (gallons)
 

Randy Holmes-Farley

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Im not a fan of random additions of EDTA because while it may reduce toxicity, it will also reduce bioavailability of metals that organisms need. I would not know how much to advise dosing since it would depend on the concentrations of metals in the tap water.
 
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