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Discussion Starter · #1 · (Edited)
FWIW: Glutaraldehyde (and iso/polymeric forms thereof) probably won't be doing anything that's any different than any other aldehyde. Aldehydes polymerize proteineic structures, "fixing" or "plasticizing" them. This is what happens when a body is embalmed.

From: http://publish.uwo.ca/~jkiernan/formglut.htm

Reaction of formaldehyde with proteins

The aldehyde group can combine with nitrogen and some other atoms of proteins, or with two such atoms if they are very close together, forming a cross-link -CH2- called a methylene bridge. Studies of the chemistry of tanning indicate that the most frequent type of cross-link formed by formaldehyde in collagen is between the nitrogen atom at the end of the side-chain of lysine and the nitrogen atom of a peptide linkage (Fig. 2), and the number of such cross-links increases with time (Gustavson, 1956). The tanning of collagen to make leather is comparable to the hardening of a tissue by a fixative (Hopwood, 1969). The fixative action of formaldehyde is probably due entirely to its reactions with proteins. Initial binding of formaldehyde to protein is largely completed in 24 hours (Helander, 1994) but the formation of methylene bridges proceeds much more slowly. Substances such as carbohydrates, lipids and nucleic acids are trapped in a matrix of insolubilized and cross-linked protein molecules but are not chemically changed by formaldehyde unless fixation is prolonged for several weeks.
With that said, once you plasticize the phospholipid bilayer of a cell, that cell ceases to function. It dies, degrades and, presumably, is consumed as a ready source of immediately usable organic material. For you home brewers out there, this may be comparable to using spent yeast hulls to feed a growing yeast population, although, IMO, this is more likely due to available nitrogen than carbon. See here for more: http://en.wikipedia.org/wiki/Yeast_assimilable_nitrogen

All of this being said, "Bio available carbon" is probably not the key idea in what's happening with the use of aldehydes so much as it is the nitrogen, ATP, ADP and other key ingredients to cellular energy transfer and function, being more available when simple cells rupture and spill their cytoplasmic contents. Glutaraldehyde itself is certainly not friendly to any living organism as it is, so it would be erroneous to say that it is in and of itself useful. After all, if you've got mulm or especially CO2, you've got MORE than enough "Bioavailable Carbon" at your disposal. Carbon is generally not difficult commodity to come by. It's everywhere. And technically "Organics" ONLY refer, in the strictest sense, to CARBON containing compounds. Anything else is "Inorganic".

If you're wondering why most plants aren't as susceptible to the action of aldehydes, you will note that plant cells tend to have a tougher construction than most other life forms. They have 2 cell "walls", as it were.

http://www.enchantedlearning.com/subjects/plants/cell


You can see by comparison to most other, more delicate life forms, why most plants are tough SOB's.

So, anyway, maybe that's of interest to someone. IDK. Good luck.

P.S. Paraformaldehyde is dirt cheap at the big box stores. It can be found as septic treatment in the camping/RV sections. There is really never, ever, any need to buy overpriced aquarium products if you know what you're looking for and how to use it. Aquarium products are made by middlemen trying to make a buck. Why cater to that when the amount of glutaraldehyde in a gallon of Flourish Excel costs no more than $1.00 in reality? This is your bottom line though I guess. Do with it what you will.
 

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Great first post! If you can come up with another thousand of those you certainly receive some credits;)
 

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I enjoyed your write up - it was a good read.

I do however question using paraformaldehyde instead of glutaraldehyde. The structures are quite different and glutaraldehyde is known to completely break down fairly quickly (within a day or so) into CO2 which either degasses from the water or is absorbed by plants. I do not know the breakdown reaction or half life of paraformaldehyde or for that matter the health effects of using it regularly, so without seeing further research I'd advise caution for anyone looking for an alternative to excel or the cheaper glutaraldehyde.
 

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Discussion Starter · #5 · (Edited)
It's true that paraformaldehyde can depolymerize fairly quickly, especially in basic environments, and evaporate from solution over time. It is a basic gas.

However, it is used commonly for ich in aqueous form, probably somewhere around it's saturated state of ~37%, although I'm venturing a guess there. That's industry standard bulk aqueous formalin. You only need a very small amount to do the work it needs to do in that case, which is doing the exact same thing that glutaraldehyde, and any other aldehyde are doing: Plasticizing delicate cell walls. That's why the flagellate stage of ich is susceptible to such attacks, much the way algal and bacterial cells are.

Glutaraldehyde is almost 4 times heavier, being a butyl structure, and less likely than formaldehyde to gas off. Formaldehyde is built about a single carbon. Methane, vs Glut's Butane.... much higher vapor pressure there. But it's totally viable by any measure. You're using such incredibly miniscule amounts of aldehyde that it simply doesn't matter. I've had a face full of formaldehyde gas in the lab before and while intensely unpleasant, we aren't talking about anything like that level of risk or general overall suckage.

So, take it for what it's worth I suppose. But I guess my point overall is that the idea of Excel being "a source of organic carbon", aside from being redundant, is misleading on the whole. It isn't a significant source of anything. The results of using it on a living system however, are, but those results likely far exceed the presence of mere carbon.

Anyhoo, thank you all. I look forward to getting to know you and all you can teach me! :)
 

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But I guess my point overall is that the idea of Excel being "a source of organic carbon", aside from being redundant, is misleading on the whole. It isn't a significant source of anything.
I've come to agree with you on this point based on my experiences over the years using excel. I don't think it aids plant growth much (if at all), but it kills BBA with ease and for that it has my support! I once had BBA so badly every leaf surface was covered in it in my 55g tank, with no hope in sight I eventually tried overdosing excel and within a few weeks the tank was completely clear of it. Amazing stuff.

I think the idea that excel is a source of organic carbon is technically correct if it acts like gluteraldehyde. Apparently excel is polymerized gluteraldehyde which is supposed to be more stable and less toxic, but who really knows exactly what excel is since it is proprietary. Anyway, if it breaks down like gluteraldhyde then it becomes glutaric acid and then CO2 gas under aerobic conditions which could conceivably feed plants, though what concentration of CO2 is reached with any particular dose and how quickly is probably a tiny amount that doesn't appreciably help plants grow faster.

See http://msdssearch.dow.com/Published...ides/pdfs/noreg/253-01447.pdf&fromPage=GetDoc and page 9: http://www.prirodni-akvarium.cz/clanky/Glutaraldehyde.pdf
 

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Discussion Starter · #7 · (Edited)
Edit: I must apologize. I took a glance at gluteraldehyde and counted 4, not 5 carbons, and I was thinking "Glutaric acid? Why not butyric acid?", but it's a pentyl (5 carbon), not a butyl (4 carbon) backbone. I went back to try to "strike through" the butyl comment, but evidently my BBcode is rusty. heh.

It would be kind of fun to run excel through a quick & dirty analytical battery, but having played a hand in the chemical wholesale industry before, I wouldn't be at all surprised if they're just using the cheapest aldehyde they can find while maintaining a completely nonsensical, non IUPAC compliant trade name like "polycycloglutaracetal". That name does not make much sense BTW. It's mostly improper, though it does convey some inherent characteristics of the compound, as it must, in order to be sold or transported.

After all, this is a company who's selling a $5.00, 5Lb bag of potassium phosphate in 504 liters of solution, for almost $8,000 in the form of "Flourish Phosphorus" at 4.5g/L!!!!!! That's dirty & rapacious, albeit creative. ;)

If it is truly a cyclic isomer of the aldehyde, then hydrolysis would be the primary route of ring opening, thereby lending a strong clue to the nature of the weak bond holding the ring together. Probably oxygen. But in the end, it's probably going to be gluteraldehyde one way or the other.

EDIT: Oh, the gluteraldehyde wiki has it right here:
https://en.wikipedia.org/wiki/Glutaraldehyde
Like other dialdehydes (e.g., glyoxal), it does not exist as the dialdehyde but as the hydrate. These hydrates adopt several structures.[2]

Monomeric glutaraldehyde can polymerize by aldol condensation reaction yielding alpha, beta-unsaturated poly-glutaraldehyde. This reaction usually occurs at alkaline pH values.
But yeah, the aldehyde functional group is really the primary moity of concern. It's responsible for all the action. The metabolic products of the structure it's attached to, be it one carbon long or a dozen, is mostly insignificant.

Frankly, I was curious to know if it was even worth trying. Thank you for the heads up! :D

Snazzy! It's kind of funny too, the 1,5-pentanediol anaerobic product. I wonder if the fish get high? :p
 

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Your main objection seems to be about price but you know the cheapest way to get co2 is to buy a set up and pump co2 into a tank.
 

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I went back to try to "strike through" the butyl comment, but evidently my BBcode is rusty. heh.
At the bottom left there is a tiny link that says "BB code" which lists all the syntax, its a nice quick reference.

It would be kind of fun to run excel through a quick & dirty analytical battery, but having played a hand in the chemical wholesale industry before, I wouldn't be at all surprised if they're just using the cheapest aldehyde they can find while maintaining a completely nonsensical, non IUPAC compliant trade name like "polycycloglutaracetal". That name does not make much sense BTW. It's mostly improper, though it does convey some inherent characteristics of the compound, as it must, in order to be sold or transported.
I had the same thought back when I was still in college and worked over the summer in one of the labs. We had all kinds of tools and machines at our disposal but I was too busy with lab work to run any samples. The name is pretty nondescript isn't it?

After all, this is a company who's selling a $5.00, 5Lb bag of potassium phosphate in 504 liters of solution, for almost $8,000 in the form of "Flourish Phosphorus" at 4.5g/L!!!!!! That's dirty & rapacious, albeit creative. ;)
Exactly! Creative to say the least. I once calculated out how much flourish comprehensive it would take to reach toxic 0.37 ppm copper concentrations (for cherry shrimp), and it turned out to be something like 30 gallons in a 90g tank. In contrast, you could reach the same concentration with a few table spoons of CSM+B. Dilute is right! I can't tell you how many times I've seen people with all kinds of plant deficiencies because they follow the guidelines instead of 10x or 20x overdosing it.

Snazzy! It's kind of funny too, the 1,5-pentanediol anaerobic product. I wonder if the fish get high? :p
Haha, wouldn't that be something! The oral LD50 dose for rats is 2000mg/kg, but given that fish would absorb it through the gills into the bloodstream it is probably lower. Of course, the fish would probably be dead before they got high because it is only produced in anaerobic conditions! Food for thought though :)

http://www.lookchem.com/1-5-Pentanediol/

mistant, I hope you stick around, I've really enjoyed your posts and I can see you have a lot to offer the forum :)

We've got a couple of ongoing investigation threads (http://www.aquaticplantcentral.com/forumapc/algae/89126-organics-analysis.html) and some interesting data in the stickies here:http://www.aquaticplantcentral.com/forumapc/plant-deficiencies/ that you might find interesting.
 

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Discussion Starter · #10 ·
LOL, I was thinking maybe it might soak out from anaerobic layers? :p

Hey, thank you for the warm welcome! I look forward to moving from aqua noob to wizened enthusiast with the community's advice & knowledge. I'll definitely check out the threads there in more depth and add what I can (I've only taken a peek so far). This looks like a neat and fun place to be.

Thanks! :cool:
 
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