# Flourish Excel Vs. Metricide-14



## Captured Moments

I read this article a while back about what Flourish Excel could really be compared to Metricide 14 or glutaraldehyde. I found the article again and thought it interesting enough to post it. I don't know who the credit should go to since I don't know the author of this article.
Here it is.



> 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 http://www.seachem.com/support/Arti...or promoting plant growth in aquaria.
> [/QUOTE


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## neven

I think the arguement of metricide vs excel has been Beaten to death already.

They are both Glutaraldehyde, that is known, that is the component that makes us really use caution when handling. Many ignore this fact with excel but the risk is still there, its just a slightly lower concentration. Excel is formulated for aquarium use, designed to be a carbon source, and it has buffers that will aid in its use. If im wrong im sure tom barr will speak up, as i hear he worked on its formulation.

Metricide is formulated as a sterilent, it has buffers in it that help it work with its activator solution so it kills more effectively. Its still a low concentration Glutaraldehyde though, which is why we are able to use it effectively.

With both, we try to put the most in the tank possible without losing fish, without melting plants, why? so we get the most out of its algaecidal properties as well as increase the amount of available carbon. We start with the excel recommendations because they are proven dosages that are conservative, many will go beyond that though.

the argument really comes down to these points

Are you comfortable using medical grade sterilant?
Do you want the cheapest most economical solution? (think tank size)
Do you want to put only things designed for aquarium use in your tank?

for large scale, metricide wins (if you dont want co2 injected), small/nano, excel wins as the cost difference wont be felt. For medium size aquariums, its really does fall under those three questions i listed.


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## SeaHorse_Fanatic

Love Metricide. 65g planted tank grows plants like crazy with it.


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## Morainy

Forgive me, but I'm not sure that I entirely grasp this article. Is it saying that there's a health risk to humans or fish in using Excel?

I use Excel sometimes but I haven't been careful in handling it at all.


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## neven

of course its a health risk, handle it as if you would bleach, and you will be fine. Don't inhale it, don't cover your hands in it, don't ingest it, keep it out of your eyes. If you get it on you, wash it off asap.

Glutaraldehyde

excert:
"In a study simulating a complete cold sterilizing procedure lasting 12 min, the integrated sample of activated, 2% aqueous sol resulted in 0.38 ppm of glutaraldehyde measured at the operator's breathing zone. Although some irritation was recorded throughout this procedure, it was not until the end of the operation, when the equipment undergoing sterilization was being air-hose dried, that severe irritation of the eye, nose, and throat was experienced by the operator and by the investigators, who also experienced sudden headaches. "

thats pretty close to excel's concentration. Just remember though, following the bottled directions and treating the product carefully definately doesn't simulate what happened here, we have a much more limited exposure.

This is kind of the reason that diluting metricide with distilled water is very frowned upon. it greatly increases the risk for something totally unnecessary. I guess working in construction made me more aware of just what things we see as safe and normal can be quite the opposite.


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## Morainy

Wow, thanks Neven. I am definitely not as careful around aquarium water treatment and plant growth products as I should be. As well, I tend to be klutzy. Thanks for the info.


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## eternity302

neven said:


> I think the arguement of metricide vs excel has been Beaten to death already.


 LOL! So funny and yet so true!!!


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## Captured Moments

Beaten to death perhaps in some aspects but what I wanted to show from the article was that how Seachem made a seemingly more stable form of glut calling it Polycyclogluteracetal and as beaten as it may have seemed, there are allways more people and new people who like to learn about it and may not have stumbled across old threads.


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## ibenu

I dont think it has been beaten to death at all. Those of us that have done the previous research may be familiar but remember there are people who are new to this all the time. Something as simple as THROW ACTIVATOR AWAY is NOT common knowledge. And yet we talk about metricide 14 like it is.

Thanks for bringing this topic to a forefront here on the new BCAquaria. We did loose alot of info on glutes in general when we came over to this new format/home.

Lisa


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## neven

ibenu and captured moments, i may have not embelished that part well enough, i solely meant the arguement as *which is better* is rather beaten to death, not the specific pro's and cons of each. Thats why i replied with more than just that first line, so it wouldn't be just a troll post, but rather something with a point to it.

also, ibenu, I did notice that i forgot to mention throw out the activator in the BBA thread section on metricide so i added that in there, dont know why i forgot to put it in originally.


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## Nicklfire

I thought the article written in the first article was pretty interesting. I went as far as to email Seachem the article in hopes for a response, and they did.

Here is what they had to say:



> Hello Shawn,
> 
> Thank you for your question. Polycycloglutaracetal is not
> a made up name, as a Google search will turn it up.
> Glutaraldehyde has many applications that are not
> associated with aquatic systems, such as being a
> disinfectant, preservative, and fixative. Flourish Excel,
> on the other hand, was developed specifically as a carbon
> source for aquatic plants and is therefore a better
> option, in my opinion. Excel is a very unique product, as
> its ingredients mimic photosynthetic intermediates, thus
> saving your plants energy that they would otherwise have
> to utilize for photosynthesis. To my knowledge, the
> active ingredient in Flourish Excel and the way the
> product is produced allows for a much safer application
> than using just glutaraldehyde. Since Flourish Excel is a
> product that has been researched and tested by us for
> aquarium applications, I am confident in saying that this
> is the better choice between the two. We do not encourage
> anyone to experiment with glutaraldehyde, as it is
> dangerous. Glutaraldehyde is a chemical sensitizer, may
> cause rashes, and is rough on delicate tissue (mucous
> membranes, eyes). For further information on Flourish
> Excel, please see the following link to the Material
> Safety Data Sheet: http:
> 
> www.seachem.com/support/MSDS/FlourishExcel.doc.pdf
> 
> Please let us know if we can be of any further assistance.
> 
> Seachem Support 100215


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## Mferko

i just used fluorish for the first time last night, about 1/4 of a capfull to a 10g tank, thats not too much is it? fish seemed fine this morning...
i had just put new driftwood and new substrate/plants in there and wanted them to do well.


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## neven

for those looking for the metricide 14 msds click here

If you compare the health hazard Section its nearly identical. Also remember that we are skipping the activator in metricide, this keeps it in a much more stable form, as once you add the activator, it lasts 14 days..

Most Seachem Replies on the danger of glutaraldehyde, but they fail to mention the concentration they are speaking of and the use. On top of that the use of metricide is trays filled with this stuff, thats a huge surface area, so of course the respiratory risk will be increased.

on 07 July 2006 the msds seachem released on flourish stated it as an Aqueous solution of glutaraldehyde

on 28 September 2009 the msds changed to "an Aqueous solution of polycycloglutaracetal"

for some reason now google docs wont show the old msds any more that were linked in this post on planted tank

Keep in mind that in 2006 metricide 14 as an alternative was very rarely even mentioned, but in 2009, the information about it was on aquarium forums everywhere. There formula may have changed, but many pro metricide users think otherwise.

Where i stand in this? as i stated earlier, its what works for you. Im simply pointing out that the risks and dangers are both the same, and its really splitting hairs to say excel is 'safer.' PH wise, flourish Excel is 5.5, Metricide 14 is 3.2-4.3 (lemon juice is 2.4)


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## neven

Mferko said:


> i just used fluorish for the first time last night, about 1/4 of a capfull to a 10g tank, thats not too much is it? fish seemed fine this morning...
> i had just put new driftwood and new substrate/plants in there and wanted them to do well.


Make sure you have excel, as theres a bottle labelled just as flourish, and its a micro nutrient fertilizer, which can still be useful, but not related to your question .

cap sizes vary depending on the size of excel container. But if its a smaller bottle (not 1 gallon), should be 5ml = cap size. 1 thread = 1 ml. First dose you use 5ml at 10 gallons. after that its 1ml /day minimum, but as long as you don't have sensitive plant species, going 1/4 cap a day shouldn't do harm.

overdosing is to remove algae (10-14day cycle), otherwise the recommended dosage will give you the carbon you need for decent growth for a medium planted tank


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## Mferko

neven said:


> Make sure you have excel, as theres a bottle labelled just as flourish, and its a micro nutrient fertilizer, which can still be useful, but not related to your question .
> 
> cap sizes vary depending on the size of excel container. But if its a smaller bottle (not 1 gallon), should be 5ml = cap size. 1 thread = 1 ml. First dose you use 5ml at 10 gallons. after that its 1ml /day minimum, but as long as you don't have sensitive plant species, going 1/4 cap a day shouldn't do harm.
> 
> overdosing is to remove algae (10-14day cycle), otherwise the recommended dosage will give you the carbon you need for decent growth for a medium planted tank


yea i put in the flourish, whoops


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## skabooya

Thanks for this thread guys. I havent been on as often as i like and was gone for quite some time while i was pregnant and had my baby. I never came across a metricide discussion. very interesting. Good to know.
Im sticking with my Flourish Excel lol


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## fkshiu

I prefer to think of glutaraldehyde as simply a chemical that just happens to have uses as a medical-grade disinfectant, an algaecide and as a carbon source for aquarium plants. As long as you are aware of its pros, cons and dangers, it's not a matter of what is "better".

There are multitudes of chemicals that have multiple uses. Take sodium thiosulfate for example. Aquarists routinely use it for dechlorination without a second thought, but it's also used as a fixing agent in filming processing, among many other things.

Sodium thiosulfate - Wikipedia, the free encyclopedia


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## Morainy

Nicklfire, that's very interesting! Thanks for posting. I always appreciate it when a company takes the time to write back an informative letter rather.



Nicklfire said:


> I thought the article written in the first article was pretty interesting. I went as far as to email Seachem the article in hopes for a response, and they did.
> 
> Here is what they had to say:


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## globali

> Love Metricide. 65g planted tank grows plants like crazy with it.


Hi there,

I just learned about Metricide 14 from many forums
and found that thread very good as for general data,
but I do have few simple questions about Metricide.

1. When most people say they use Metricide do they
mean that they use Metricide 14, (written on the label).

2. As I understand, most people dose with Metricide 14
as it is, with no dilution and without using the activator.

3. What is the dosing measurement with Metricide 14,
For example; when one buy Seachem Flourish Excel
it's written on the label, 5ml for 000 liter once a week.

‏


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## effox

globali said:


> Hi there,
> 
> I just learned about Metricide 14 from many forums
> and found that thread very good as for general data,
> but I do have few simple questions about Metricide.
> 
> 1. When most people say they use Metricide do they
> mean that they use Metricide 14, (written on the label).
> 
> 2. As I understand, most people dose with Metricide 14
> as it is, with no dilution and without using the activator.
> 
> 3. What is the dosing measurement with Metricide 14,
> For example; when one buy Seachem Flourish Excel
> it's written on the label, 5ml for 000 liter once a week.
> 
> ‏


1. Yes that is correct.
2. Yes, don't dilute and don't use the activator.
3. "2.9 mL for every 50 gallons of water, works out to 0.06mL per gallon" as per Neven's instructions in the http://www.bcaquaria.com/forum/plants-algae-ferts-ei-co2-lighting-13/basic-guide-carbon-dioxide-81/ thread.

Cheers,
Chris


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## globali

> "2.9 mL for every 50 gallons of water ... "


Thank U Chris,

That is 2.9 mL 190 Liter.

O.K. Now I'm thinking loud, my apology
but it's easy for to understand like that.

1. Suppose one have 200 Liter of planted aquarium.

2. One buy 1 gallon of Metricide 14 (1 gallon = 3.78 Liter = 3,780 mL).

3. Suppose one will doze once every week (3,780 mL : 2.9 mL = 1,303 weeks).

4. One gallon of Metricide 14 will last for 1,303 weeks.

5. 1,303 weeks = 27 years!

6. WOW, So Suppose one dose twice a week 
one gallon of Metricide 14 will last 13 years apx.

7. If one will doze every other day and he have one gallon
of Metricide 14 he can use that for about 3 years!

1. Did I calculate right.

2. If so, doe's Metricide 14 will be effective
for such a long time, no expiration date.

3. Where is the best place to keep Metricide 14 after opening.

I do ask all of that because I couldn't find Metricide 14 here in Israel,
Seachem Flourish Excel is relatively higher in price and therefore 
I do consider to order 1 gallon of Metricide 14 from abroad.


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## neven

here is the whole article quoted i posted



neven said:


> *Liquid Substitutions for co2*
> 
> CO2 is the best carbon source for your plants, but there are liquid substitutes one can use with nearly the same results growth wise. Just like fertilizers, these substitutions are chemicals and should be handled like you would handle bleach. Here are the recommended daily dosages, and it is best to do them at the start of the photo period as you would with EI dosing. These dosages are are based on excel's directions but many do exceed them. Generally speaking doubling the dosage is still in the safe zone, but when you go above four times the dosage i've heard mixed results. I personally found 4x per day to work great for my set ups. If you like math, i've read that Tom barr doesn't recommend going beyond 3 ppm per day.
> 
> There are certain plants that are sensative to these additives, some more than others. These plants will melt away from it.
> -Algae!!! (big plus!)
> -Anacharis (egeria densa)
> -Vallisneria
> -Subwassertang
> -pellia
> -Moss balls (they are an algae)
> -Some mosses**
> -Riccia fluitans**
> 
> ** denotes that direct contact or above recommended dosages required. With mosses i've had java moss and flame moss fine.
> 
> *Excel* (1.5% glut)
> 5 mL for every 50 gallons of water, works out to 0.1mL per gallon
> 
> *Metricide* (2.6% glut)
> 2.9 mL for every 50 gallons of water, works out to 0.06mL per gallon
> Since the product isn't activated (you throw out the activator, NEVER USE IT), the product lasts 2 years rather than the 1 year shelf life stated on the bottle


if you read the first paragraph it says daily dose. The reason most people dose daily is because the solution dosed at safe levels rarely lasts more than 2 days in a tank. if you want to dose less often, you can probably get away with dosing twice a week, but the dosage will need to be increased. You can safely dose double to triple the dose daily before livestock are at risk, so i'd say by dosing 8.5 mL twice a week for 50 gallons of water would be the most beneficial.. Why is it most beneficial? because most tanks have too much light without a sufficient carbon source, so by increasing the available amount of carbon, it allows the plants to better utilize the light available and out compete algae. Toxicity limits the amount we can put in of both excel and metricide.

The math you need to do is comparing the cost of excel to metricide since thats why you are looking into it.

1.7 gallon of excel = 1 gallon of metricide.

$90 for excel 1 gallon (bigalsonline.ca), so $153 for equivalent of 1 gallon of metricide
here metricide is $19.50 for 1 gallon.... hmm which is cheaper.

The dosage math i've done already in the quoted post. You choose how comfortable you are, going 1x, 2x, 3x or even 4x (above i never recommend). If you have no fertilizers, and an innert substrate, its pretty useless going above 1x because you'll be limited by fertilizers. If you get black fuzzy's (bba) going 2x/3x and/or raising the light a little bit will likely help reduce its occurance

as for storage. With kids, a key locked cupboard. Without kids but with pets, a latched cupboard. Without either wherever you want that is cool and dark. Just remember that if kids do come over, they might find it. I use a 250 mL bottle to dose from with a syringe. makes life much easier.


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## globali

> here is the whole article quoted i posted ...
> if you read the first paragraph it says daily dose ...


Thank U very much, neven.

I read and re-read all your post carefully and find
the data very useful, well now I guess the only
issue left is 'Dosing addiction' vs. CO2 vs. As is.

Unless if it possible to dose excel/metricide with
Dosing Pump, I will look and learn that issue.


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## neven

peristaltic pumps can be used to dose anything form of liquid fertilization. They can be costly though for a full fert set up. Plus the macro ferts will need to be made into 2 week batches to avoid growth in the mixes, an issue you do not have with dry dosing.


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## globali

> peristaltic pumps can be used to dose ...


Thank U very much, neven.

There is a lot of thinking 2do.


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## globali

Hi everyone,

Cidex Plus contain alkaline glutaraldehyde.
Metricide14 contain buffered glutaraldehyde.

1. What is alkaline glutaraldehyde and
how can we tell that it is good 4 planted aq'.

2. Is the alkaline glutaraldehyde in CidexPlus
is buffered as well just like Metricide14.

3. I read the the MSDS of CidexPlus but it said
nothing about other components that may be in
CidexPlus and may be relevant 4 planted aq'.

Here in Israel there is no Metricide14 and
I could hardly find so far CidexPlus 28.

4. Cidex (MSDS).

5. Metricide14 (MSDS).

6. There is other product here called Cidex Opa (MSDS) 
but it build with ortho-phthalaldehyde and I wonder
if that will be good as CidexPlus 28/Metricide14.

7. There is other product here called STERANIOS 2% (MSDS)
It is also 2% glutaraldehyde solution and I wonder
if that will be good as CidexPlus 28/Metricide14.

As for STERANIOS 2% I read here that it contains:
Alcohol denat, Aqua (Water), Glycerin, Acrylates/C10-30 Alkyl Acrylate Crosspolymer,
Ethoxydiglycol Oleate, Bisabolol, PEG-4 Caprylic/Capric Glycerides, Aminomethylpropanol,
Phenoxyethanol, CI 42051, Parfum (Fragrance).
BUT NONE OF THOSE are mentioned at the product MSDS.

Any comment will be appreciated.
.
.
.
.


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