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Discussion Starter · #1 ·
Does anyone have a link or know of someone that has actually done scientific testing of plant growth using this product?

Since I started dosing with glutaraldehyde, I've noticed my plants in my new aquarium seem to be doing better, but I'd like to know if anyone has actually done a real controlled experiment- 2 tanks, identical plants, identical lighting, one with excel, one without.

It's easy to attribute the passage of time and the plants adapting to my tank as "doing better with Excel" and I don't want to fool myself and keep dosing and buying this, if it is doing nothing.

I have another question. What part of the Calvin Cycle and carbon fixation-


is the glutaraldehyde actually supposed to be entering into?

http://en.wikipedia.org/wiki/Glutaraldehyde

 

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The active ingredient is actually an 'isomer' (an atrocity to chemical nomenclature) of glutaraldehyde called polycycloglutaracetal by Seachem. It is also part of a propitiatory that is a top secret of Excel. Furthermore, they are unwilling to release their data until they can get a patent. (http://www.seachem.com/support/forums/showthread.php?t=80)
But they claim that they developed this through years of testing. You could check the Barr Report, however, as he has probably has done something with this.

As to where it enters the calvin cycle, I think only one could speculate. Someone could postulate a pathway where both aldehydes are oxidized to carboxylates and then further oxidized alpha to the carbonyls to alcohols. Then decarboxylated to some 3 carbon compound that could be further transformed to glycerate or some phosphate ester thereof. But I'm no biochemist.
 

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Theories I have read:
Glutaraldehyde breaks down to CO2 in the water providing more CO2 for plant(but then why doesn't a bottle of Excel break down on its own, maybe it requires light)

Glutaraldehyde forms backbone of glutamine, allowing plants to use nitrates faster(Then its not really an "organic source" of carbon)

I am not sure but am interested as well.

And with regards to your first question, email SeaChem. Their support people seem more than happy to answer questions from hobbyists.
 

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Not of much use to this thread, but just be careful when you handling the Glutaraldehyde. That stuff can cause some serious damage.
 

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(but then why doesn't a bottle of Excel break down on its own, maybe it requires light)
You know, you may have landed on something here- I know I've read some threads where Seachem recommended not storing Excel in clear containers due to light exposure... but I'm reasonably sure also I've read that using Excel made no change in measured CO2 levels? (not that I can remember where I read that... or what type of measure was being used)
 

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You know, you may have landed on something here- I know I've read some threads where Seachem recommended not storing Excel in clear containers due to light exposure... but I'm reasonably sure also I've read that using Excel made no change in measured CO2 levels? (not that I can remember where I read that... or what type of measure was being used)
Or it could react with water

But I doubt it forms CO2

If it did, it would change the tanks pH, and a drop checker would show this.
I'm not saying it doesn't form CO2, or that it doesn't change the pH, but if it does change the pH, it doesn't mean that it forms CO2
 

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No, I think you're taking the correlation between CO2 and pH too far, since there are so many buffers in a planted tank (ie the plants themselves) that make that relationship a bit more complex.
This is true, but drop checkers are used to measure pH, well, they measure the pH of the air inside the drop checker, which changes based on the gases in the aquarium water.
 

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The CO2 does come from the product.
But does not break down except by bacteria and is released into the water.
The transformation occurs on the plant cell, not out in the water.

Light breaks the bonds.
That is well known.

Regards,
Tom Barr
 

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Discussion Starter · #10 ·
I found this article very interesting a while back and thought I'd share-

http://www.springerlink.com/content/hx07d33kyqtpefpa/

It seems there is no breakdown at all, under sterile conditions, of glutaraldehyde into CO2. It relies on metabolism by life.

Material balance studies of glutaraldehyde in a river water–sediment system demonstrate that glutaraldehyde preferred to remain in the water phase. Glutaraldehyde was metabolized rapidly under both aerobic and anaerobic conditions. The pseudo-first-order half-life of catabolism, based on the loss of glutaraldehyde from the water phase, was 10.6 h aerobically and 7.7 h anaerobically. In contrast, under sterile conditions at pH 5 or 7, no appreciable degradation of glutaraldehyde was observed over a 31-day period. At pH 9, about 30% of the glutaraldehyde degraded over the same period. The major degradate was identified as 3-formyl-6-hydroxy-2-cyclohexene-1-propanal, a cyclicized dimer of glutaraldehyde. The extrapolated half-life of abiotic degradation was 508 days at pH 5, 102 days at pH 7, and 46 days at pH 9. Under aerobic conditions, glutaraldehyde was first biotransformed into the intermediate glutaric acid, which then underwent further metabolism ultimately to carbon dioxide. Metabolism of glutaraldehyde under anaerobic conditions did not proceed ultimately to methane, but terminated with the formation of 1,5-pentanediol via 5-hydroxypentanal as an intermediate.
But it is not this bacteria, etc. released CO2 that is the source of Excel's purported benefits, right? They specifically say "photosynthetic intermediates" repeatedly on the product's page. My last tank was saltwater and it is common to dose vodka or vinegar to give the tank's bacteria a carbon source so that they use up the tank's nitrate, etc. in their growth and respiration. I'd like to think Excel is doing something fancier than this.

I'd still like to know where exactly Seachem says Excel is entering the photosynthetic pathway and as what "intermediate".
 

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Scientific testing???

There's really no reason for anyone to carry out a test unless it's either to disprove the products claims or reproduce (copy) the Seachem formulation. I don't think I'm capable of running two systems exactly the same where the results could have reproducible thus meaningful results.

SteveU
 

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Discussion Starter · #13 ·
By scientific testing, I simply mean two tanks with the same lighting and same plants, one with excel, one without. You should get an aquatic version of this-

 

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There's really no reason for anyone to carry out a test unless it's either to disprove the products claims or reproduce (copy) the Seachem formulation.
You're assuming no one cares how or why this product works...
 

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You're assuming no one cares how or why this product works...
Sorry, I'm not assuming anything. The OP was asking in a round-about way if the product really works or if the positive results he's seen are just coincidental.

My only point is at the hobbyist level I wouldn't call side by side comparisons scientific results. It would take a serious effort using multiple tanks and procedures (lots of time and money) to come up with any evidence one way or the other. Two five gallon tanks side by side wouldn't provide enough data to do more than speculate.

I think it's accepted that the product works (delivers a carbon source) but just not as well as CO2 in most cases.

SteveU
 
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