# information about Glutaraldehyde



## neilshieh

i went to taiwan last summer and in one of my visits to a fish store the guy told me to get a chemical 
C5H802 and he said it converts O2 in the tank to CO2. i looked some places about what the chemical was and got mixed results. only recently did i possibly think it was Glutaraldehyde. did a search on wikipedia and the chemical formula did match. 
is this really what it does? 
it'd explain the consequences of overdosing.

he also said it was a aquarium secret... and not many people know... much less i come to the US and find that its used as the cheaper generic excel.


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## HeyPK

Aquarium secret, hunh? Any organic molecule that is metabolized by bacteria or other living things, such as snails or fish or fungi or yourself will give off CO2. This magic compound can't change O2 to CO2; that would require oxygen atoms to be converted to carbon atoms or carbon atoms to come out of nowhere! That sort of thing does not happen. The organisms that metabolize the organic molecule take in the O2 and they give off the CO2. The carbon in the CO2 comes from the organic molecule. Glucose, C6H12O6, or sucrose, C12H24O12, will be broken down quickly in your aquarium and CO2 will be produced. You and your fish may not like the resulting bacterial cloudiness and films, or the lowered O2 levels, however. Your fish are taking in O2 and giving off CO2. You take in O2 and give off CO2.


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## neilshieh

looks like that dude did not know what he was talking about... but then again, chinese doesn't really translate to english really well. 
so what makes overdosing excel dangerous? is it the concentration of Glutaraldehyde or because there is too much co2 dissolved in the water which in turn suffocates the fish.


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## HeyPK

Gluteraldehyde is toxic except in very low concentrations. It is, according to wikipedia, used as an algecide and it kills algae at concentrations between 0.5 ppm and 5 ppm. Excel does not have gluteraldeyde, rather a polymer of an isomer of gluderaldehyde. I am pretty sure that it is the gluteraldehyde, rather than CO2 that causes problems.


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## Seattle_Aquarist

Hi Neil,

I believe the chemical reaction would be:

C5H8O2 + 6 O2 → 5 CO2 + 4 H2O

If I remember my chemistry correctly, what it appears happens is the "extra" carbon (C) and hydrogen (H2) molecules in the Glut bond with the oxygen (O2) in the aquarium water creating molecular CO2 and water. If so, using the Glut reduces the oxygen content of the water and could result in fauna distress.


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## neilshieh

so if excel contains a polymer of isomer of Glutaraldehyde, then why is the distilled version of Glutaraldehyde being used in place of excel, besides the obvious price difference.

so is Glutaraldehyde used by the bacteria in water or does it "seemingly" form CO2? 
also does a high CO2 push out the available content of dissolved O2? moreover is it possible to have high dissolved CO2 content and high O2 content? sorry but i'm taking chem next year so this stuff seems a bit weird.


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## medicTHREE

neilshieh said:


> so if excel contains a polymer of isomer of Glutaraldehyde, then why is the distilled version of Glutaraldehyde being used in place of excel, besides the obvious price difference.
> 
> so is Glutaraldehyde used by the bacteria in water or does it "seemingly" form CO2?
> also does a high CO2 push out the available content of dissolved O2? moreover is it possible to have high dissolved CO2 content and high O2 content? sorry but i'm taking chem next year so this stuff seems a bit weird.


For many years Seachem tried to tell us that they were patenting the product in excel and then would tell us what it was made of. Notice the bottle says nothing. The MSDS says this polymer nonsense, but notice the rest of the MSDS is completely identical to that of products like Metricide 14, a Glutaraldehyde product.

Aqueous solution of polycycloglutaracetal is the name Seachem gives.
This is a proprietary name from Seachem. You will find no other reference to it from any other source. Seachem will not say what it is. It just so happens that the MSDS for it is identical to other diluted Glutataldehyde products. Actually, Seachems is often worded STRONGER than others.

Also, Glut does not turn into CO2, it breaks down into a carbon source. There is a difference. Both co2 and excle/glut have their own toxicities.

For for info on some discussion we've had at TPT, see these two threads:
http://www.plantedtank.net/forums/f...104038-metricide-14-replace-excel-dosing.html
http://www.plantedtank.net/forums/f...ers/103970-will-excel-provide-enough-co2.html

They both run in a bit of a circle, as some people are overly cautious, but the information is there.


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## medicTHREE

Also, it seems as though Azoo is marketing a similar product now, named Carbon Plus. I am sure it is another glut solution, or is worthless like the citric acid solution from Brightwell.


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## ray-the-pilot

medicTHREE said:


> Also, it seems as though Azoo is marketing a similar product now, named Carbon Plus. I am sure it is another glut solution, or is worthless like the citric acid solution from Brightwell.


Can you point me to anything that can support this statement? I'm especially interested in why you think citric acid is worthless?


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## medicTHREE

ray-the-pilot said:


> Can you point me to anything that can support this statement? I'm especially interested in why you think citric acid is worthless?


I spent a considerable amount of time and sum of money trying to develop a similar product. Merely containing carbon does not make it bioavailable. If it did, sucrose(table sugar) would be of huge benefit when just dumped into the tank. It has twice as much carbon as citric acid does.

My testing showed no change in plant growth in a quadruple blind test. No difference in plant mass between citric acid dosed tanks and those with no dosing at all. Tanks were dosed using EI in the first test, and then with no dosing and followed by RootMedic line of dosing. Obviously, I was looking for something to sell and while it might be "skewed" I can assure you that if I found something that had worked it would be on my website. Further, if citric acid worked, we'd be dumping that powder in our tanks!

Glut breaks down readily(light sensitive, for starters) and works well for our purposes of low tech tanks, when not overdosed. Extreme caution should be used when handling solutions over 2%, but even at 2% solutions could cause health problems if handled carelessly.


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## ray-the-pilot

medicTHREE said:


> My testing showed no change in plant growth in a quadruple blind test. No difference in plant mass between citric acid dosed tanks and those with no dosing at all. Tanks were dosed using EI in the first test, and then with no dosing and followed by RootMedic line of dosing. .


I think the reason you did not see any difference in plant growth using citric acid is because you did not use enough and you are adding it in an uncontrolled manner.
In my experiments I found that for a 50 gal well planted aquarium the plants will take up about 1g of citric acid per hour. With sufficient citric acid, plants will grow without any CO2 and will even grow in the dark.
Maybe you might want to take this discussion to a new thread or off line.


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## medicTHREE

ray-the-pilot said:


> I think the reason you did not see any difference in plant growth using citric acid is because you did not use enough and you are adding it in an uncontrolled manner.
> In my experiments I found that for a 50 gal well planted aquarium the plants will take up about 1g of citric acid per hour. With sufficient citric acid, plants will grow without any CO2 and will even grow in the dark.
> Maybe you might want to take this discussion to a new thread or off line.


I should have clarified. At a reasonable dose, I did not find any usable results. I have seen controlled lab tests that indicate similar results to what you say, but have never tried so myself. I'd love to have a longer discussion about this though, if you'd like. Either email me([email protected]) or start a new thread so we don't completely destroy this one(but pm me so I don't miss it).

I'm all for active discussion, so feel free to start a thread on this. That being said, my statement stands that brightwell's product is essentially worthless, as it likely only contains a few grams total of citric acid...


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