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What's in AE excel/easycarbo

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3 Jul 2007
Bexley, Kent
I don't know what is used in AE's carbon or Easycarbo but I know for sure that Seachem's Excel is not a solution of glutaraldehyde. It is a solution containg Polycycloglutaracetal which is safer to use than Glutaraldehyde and acording to Seachem is more easily utilised by the plants. Glutaraldehyde is pretty nasty stuff and I'd be surprised if AE and Easy life use it.

To what I read on other forums it does appear that some people have used glutaraldehyde with success so who knows.


davidcmadrid said:
" In 1999 the HSC approved a proposal that exposure to glutaraldehyde should be controlled to a Maximum Exposure Limit (MEL) of 0.05 parts per million, for both short-term (15 minutes) and long-term (8 hour time-weighted average) exposure. Peak vapour concentrations should not exceed this level.This change was prompted because of the impossibility of determining a safe exposure limit for glutaraldehyde. MELs require employers to prevent exposure to the substance "

http://www.rcn.org.uk/__data/assets/pdf ... 001362.pdf

The medical industry is working on ways of phasing out the use of this product currently.

Seachem are naturally tight lipped about their concentration but only because US federal law is loose in regards to this aldehyde. They are also keen to avoid associating themselves with the notion that it kills algae. For the moment I have stopped using this product and sealed it. I am concerned about exposure through evaporation of the tank into the sitting room , and rooting around in the tank after a water change at which point its concentrations are higher. Quite honestly i was looking into its contents to see if i Could make it myself and it now clear that this is not something i want to be touching at all.

AE excel/easycarbo

JamesC said:
I don't know what is used in AE's carbon or Easycarbo but I know for sure that Seachem's Excel is not a solution of glutaraldehyde.


According to their Mandatory MSDS it is , beyond Seachem are not saying anything. Its probably not fair to AE to have that discussion here though.
Re: AE excel/easycarbo

I'm afraid it isn't glutaraldehyde. Seachem are quite open about this and have stated many times that it isn't glutaraldehyde. MSDS doesn't tell you anything about what is actually contains.

One of Seachem's many postings
Flourish Excel can be used with snails and shrimps in the tank. Used as directed Flourish Excel is safe to dose to an aquarium. It is not actually Glutaraldehyde but, Polycycloglutaracetal. Polycycloglutaraldehyde is an isomeric form of glutaraldehyde... however it is less reactive and more easily utilized by plants as a carbon source.
Seachem Laboratories, Inc. http://www.seachem.com 888-SEACHEM

Re: AE excel/easycarbo

Generally speaking I dont understand why Seachem felt compelled to submit an MSDS with the toxic " non polymer " version but the fact is that they did and the symptoms on that MSDS match those of the non polymer version according the HSC ( UK) . In any event its been pointed out to me that in the UK when you sell a chemical in this manner you should have submitted an MSDS to the UK folks of your own and i cant find one for AEs product MSDS online so a copy of the MSDS should clear it up.
Re: AE excel/easycarbo

davidcmadrid said:
Generally speaking I dont understand why Seachem felt compelled to submit an MSDS with the toxic " non polymer " version but the fact is that they did and the symptoms on that MSDS match those of the non polymer version according the HSC ( UK) .
Seachem are a bit secretive about eactly what they have done. All I know it that it isn't glutaraldehyde but an isomeric form of it. Because it is derived from glutaraldehyde, then this is what they are alowed to put on the msds. For obvious company secrecy they aren't going to list exactly what it is composed of. I work with msds's everyday at work and they are often a bit vague about what's in them. At the end of the day they are about the health and safety issues and not about what exactly they contain.

I've done a bit of researching on this glutaraldehyde and what Seachem may have done. There are different possibilities but I'd guess they would go for a fairly simple option to keep costs down.

The chemical they state as Polycycloglutaracetal doesn't actually exist so it would seem that this name is just a generalised name. Glutaraldehyde has end aldehyde groups that are quite reactive when dissolved in water, readily forming cross-links to form polymers of varying length. They also combine with nitrogen groups in proteins to form additional cross-links. It is possibly from this where Seachem gets the name of Polycycloglutaracetal from by dissolving glutaraldehyde in water with another compound which is most likely an organic compound or an amino acid. An isomer is just a different form of the same chemical and whatever isomer that is formed can depend on different factors such as temperature or pH. So from what Seachem have said it would appear that they have created an isomer of glutaraldehyde. This would be a lot safer to handle than just glutaraldehyde by itself.

So in conclusion is Excel just a solution of glutaraldehyde? The answer I would say is no. But I would say that it is a solution of glutaraldehyde with another compound that reduces the toxicity without reducing the benefits to the plants.

Can you use a solution of glutaraldehyde by itself? Yes you could but remember it's not particularly nice stuf to handle, but should still work ok in your tank. If someone offers you a DIY liquid carbon source then please be very careful with it as there is no way of knowing exactly what is in the bottle.

I have stopped using AEs carbon product totally and sent a sample of it to the Spanish State lab via my wifes sister who works there for a breakdown. The Excel product whilst even as above has dubious contents if the holes in the cheese lined up ( really do keep out of reach of children ! ) its from a company i would assume with a broad experience and resources to get the product to work and with broad quality control measures given the sensitve nature of the product.

I have not had a response from AE to a request for a copy of the MSDS , nor details of potential toxicity to both humans and fauna alike in sufficent ( or what dose ). Initial investigations via the UK HSE and a number of other bodies suggest there is no MSDS available but in that sense its early days. Im not interested in the blurb on protecting trade secrets since it seems to me you would want to be nuts to try to make this stuff at home .. I wont be going back to using it for a number of reasons which i dont feel it appropriate to discuss just yet but i am in contact with more experienced members here than me and the local aquariast group.

At this stage , suffice to say " Go with the Excel if your using liquid carbon , no price difference and the muscle of a big lab behind the product ".
Having recently stumbled across various discussion threads relating to the use of Glutaraldehyde in the aquarium to promote aquatic plant growth, I thought I would research the topic a little more for my own edification. This is what I came up with. The commercially available product by Seachem called Flourish Excel TM has a rather oddly termed compound called ‘Polycycloglutaracetal’. Based on the curiously formulated name, it appears that Seachem just made it up to describe a concoction of aqueous Glutaraldehyde with one or more chemicals of undisclosed nature. It therefore follows, that you will not find this fictitious compound on any MSDS or official chemical register of compounds. Of course it is widely known that glutaraldehyde has algicidal properties at specific concentrations, along with uses as a fixative for electron microscopy. Glutaraldehyde is a small compound made up of a short carbon chain with an aldehyde functional group at each end. The chemical formula is HCO-(CH2)3-CHO. The terminal aldehyde groups are quite reactive and in aqueous (i.e. in water) form (> pH 7.0) glutaraldehyde molecules readily forms cross-links to form polymers of varying length. These oligo-/polymers also readily combine with nitrogen groups in proteins to form additional cross-links. Hence, this is the likely origin of ‘Poly-‘ and ‘–cyclo-‘ in the name ‘Polycycloglutaracetal’; the rest of the name is self-evident. So, as it would appear, Seachem has formulated the name to describe the behaviour of glutaraldehyde in water with the additional of some type of protein or other organic compound. The polymerisation capacity of glutaraldehyde to proteins is widely used in biomedical fields in regeneration of collagen and ligaments. Moreover, cross-linking of aqueous Glutaraldehyde with proteins involves more than a dozen different forms (e.g. isomers) depending on solution conditions (e.g. pH, temperature, etc.). These isomers are in equilibrium, so whatever isomer predominates in solution will depend on ambient conditions, and appears not to influence the beneficial net effect of the compound to plant growth. The figure provided by Seachem to describe the general structure of ‘Polycycloglutaracetal’ also corresponds well to the rationale proposed here (see

more info
[url=http://www.seachem.com/support/MSDS/PlantPackFundamentals.doc.pdf]http://www.seachem.com/support/MSDS/Pla ... ls.doc.pdf

so excel is an aqueous solution of Gluteraldehyde, with an added chain of another organic copmound to produce polycycloglutaracetal?
That would sound logical based on what I have found out thus far bearing in mind I am a layman doing research. These are of interest also :


http://www.rcn.org.uk/__data/assets/pdf ... 001362.pdf

This is recognised in the UK as a highly toxic substance that can even be absorbed through your skin ( note the caution with handling the medical profession go through and what a low bar in terms of ppm they descibe as toxic ). Now ask yourself if you put your hand in the tank after a water change or have you ever splashed any on your skin when measuring out , god forbid you got it in your eye . Given there is total secrecy surrounding this stuff the last thing you want is a DIY job without understanding or entirely trusting its background , the quality control that goes into its manufacture etc. ( think concentration and how easy it is to cross a line) . Im feeling happy to post on this matter freely as i dont believe you have to be a plant guru to take care of yourself and those who are in the same room soaking up the vapours.
Re: What's in AE excel/ easycarbo

That may be true but i dont go sticking my hands in bleach and besides which we are working with doses well in excess of what the health industry considers safe in dissolved form if AE or seachem for that matter is even 99% water. The medical profession is happy to bleach the wards down but is not happy to be using this stuff even in the most controlled manner investing a lot of energy in getting rid of it. Notice that nurses report that outlines how even a tiny micro dose can cause problems ( the super lenghts they go to to avoid inhaling the stuff far beyond a cleaner in that same hospital is required to with bleach ) and nurses have won claims against the NHS proving that despite those controls they still developed asthma. Im not using the stuff because there is no MSDS , no information about concentration and the bottle is not labeled appropriately ( nor is Excel given how the aldehyde is classified in the UK ) and besides which there is a bucket of legislation that goes back to manafucture ( where / how ?? ) that is potentially not being complied with which is conjecture at this time. Copies of Excel is just that a copy and given the whole aquarium community has been in knots for years trying to figure out whats in it im not sure that this is possible to the extent that one can say it does what excel does under various conditions and behaves as excel does given it "seems" that Seachem have managed to tame the non polymer aldehyde by the addition of other compounds and have a very well developed quality assurance structure in addition.

I asked AE several question relating to quality assurance, for a copy of the msds and active ingredient ( legally obliged to say what it is ) at what point the stuff becomes toxic and the response recieved was " ITs been used for years without problems " and i was stonewalled on the rest. My understanding is that this is a new product so how its been used for years I dont know.

I should add that my interest is born out of the fact that I purchased the product and used it for a while before deciding to stop for a number of reasons to investigate what was in it. I was quite happy with AE and found them helpful on the phone and was somewhat surprised my questions were not answered as they addressed health and safety in addition to asking for information they are legally obliged to provide. ( MCDonalds are not allowed to keep their ingredients secret , its how they are mixed that is the secret ).
From what I understand Tom Barr helped/suggested the developement of AE's "Easycarbo" product, so hopefully him or Richard should be able to clarify things.
Assuming it only contains glutaraldehyde and water the effective dose for algicidal properties is 0.1 to 0.5 ppm.
Assuming the highest effective ppm dose (0.5) is used and the liquid is diluted 5ml per 100 000ml as stated on the bottle. This results in a dilution factor of 20000. So 20000 x 0.5 for the stock solution is 10 000 ppm.

10 000 ppm is equivilent to 10 ml in 1000 ml which is 1%. If the only contents are aqaueous glutaraldehyde and if the dosing is that high.

Nurses use about 2%, perhaps a little higher or lower if it has gone off.

Also the polymerised version has a lower ability to penatrate tissue and crosslink with proteins (an important consideration when using it to fix microscope slides). Personally I'm not worried about putting my hand in the tank but I wouldn't get too close to the bottle. I don't beleive they would be able to sell it without a myriad of warnings if it was a real danger.

The amount for irritation of mucous membranes is 0.3 ppmv which I can't calculate because I don't know how big the hypothetical room is. I wouldn't sniff it to be on the safe side.

As far as risks go I'm not worried but I use more dangerous chemicals at work. I think the low level radioactivity will get me first, or I'll get hit by a car. Maybe I'd think differently if I had kids in the house.

I will of course stand corrected if (due to the fact I'm pretty tired) I've missed a factor of ten somewhere ;) .

EDIT sorry I forgot my source for the nurse percentage and irritation of mucous membranes
http://www.puricore.com/PDFs/Guideline_ ... scopes.pdf
Pages 6 and 7 of that report are the interesting ones, again the reduction in safe levels that the UK also adopted. AE stated their product is 20% stronger and it is not known that it is a polymer version that is being sold. I suppose long term the experience of other users will be interesting also just in terms of the tank.

Also if i follow your figures correctly these are for daily doses not the water change dose ,,, ever get the smell of the chemical in the room the day you do a water change ? That in my laymans view of things should if nothing else carry a warning to ensure proper ventilation when dosing it higher. Ever taken the advice to up the anti if tackling a bloom ??
If you can smell it that is bad

" It has a detectable odor at 0.04 parts per million volume (ppmv) and is irritating to skin and mucous membranes
at 0.3 ppmv. "

I agree proper ventilation is important.

I don't know if it smells myself as I don't have a very good sense of smell. I can't smell gas leaks so for something like that I don't stand a chance.

Also I calculated the daily dose 5x too high (sorry) so the stock would more likely be 0.2% or lower as I assumed a very high dose and that it is the only active ingredient.

I am still not overly worried, but maybe I am too trusting of their labels.
So what you are saying is , that it must be in high concentration e.g in the shop bottle at which point it is very toxic and the bottle should be kept sealed and not smelled. As obvious as sniffing superglue is a bad idea , it says on the bottle sniffing glue is a bad idea on the bottle. The NHS is avoiding exposure to this for even minutes. If that is the case then it stands to reason that the sole danger may only exist with the bottle itself , whilst dosing. My own sense of smell is not fantastic but yeah there was a pong on the day of dosing with water change in particular ( AE product i cant remember the excel as i was primarily using the AE one ) . My wife on the other hand due to her pregnancy can smell it a mile away ( though she can pretty much tell you whats on the frying pan next door right now ).

I dont know how long it will take to get the results back on concentration. I have given all these documents to the scientist looking at concentrations also.

It seems , generally speaking that Seachem and AE are keen not to say how much of the aldehyde is in the bottle ( if what James says is true there is a degree of obfuscation from Seachem ) but a company that wanted to make the stuff up can find out anyway from analysis ( i actually found the seachem patent application which outlined how they process it but cant find it now ) and any diy tank keeper would be absolute loopers to try and brew this up at home ( could easily be found floating belly up in the fish tank ).
I read somewhere else in a large thread about using these products to treat BBA that the reason they keep the ingredients secret was due to licensing laws on selling algaecide and pesticides.

I wonder if any have actually been screened properly through the relevant health & trading standards bodies for sale over the counter in aquarium shops due to the toxic nature of the contents.

I dont believe so. Did you notice the pong when dosing easycarbo ? have you seen the health care industries take on gluteraldehyde ?
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