# Flourish Excel - an allelochemical?



## DougC (Aug 4, 2006)

Well maybe not literally. But similar behaviour perhaps?

Having read a lot of the discussions on these fora (about Excel) and suffering from a bit too much BBA I decided to give the "Excel overdose" method a go. Well I was pleasantly astounded - After a couple of days the nasty BBA stuff duly went pale and shrank slowly away over the following weeks. I was well impressed. The water even seemed to go a bit brown during the process, as if the algae were leaking away to their doom.

My thought line was this.

I understand Excel has as an active ingedient some form of glutaraldehyde. I gather that this is similar to some photosynthetic intermediary chemicals. Having also read some of the discussions about allelochemicals (esp THE book - thanks DW) this rang a chord. 

So my question for discussion is - does this in any way help us to understand Allelopathy or to understand why Excel helps to remove Algae? Er - or neither.


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## epicfish (Sep 11, 2006)

At an overdose, it becomes toxic to the algae. Check out a discussion of it here: http://www.aquaticplantcentral.com/...3020-why-does-excel-kill-fish.html#post244493


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## DougC (Aug 4, 2006)

Yes I agree that we understand that it works. But my point was does this help to understand why it works?


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## epicfish (Sep 11, 2006)

Why it kills algae? Because it's used as a biocide. It's toxic in high concentrations. National Pollutant Inventory Substance Profile

Nothing to do with allelopathy.


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## Grayum (Jun 14, 2006)

I wouldnt say 100% that it has nothing to do with allelopathy. Flourish Excel is just DOC (disolved organic carbon) so in a tank that is not co2 injected, it would give a sudden boost to the plants (co2 being the limiting factor on growth in a natrual tank) and thus could possibly create an increase of allelochemicals. There is alos the slight possibilty that this sudden growth could help the plants "out compete" the algae, but the chances of that being true are fairly slim, as algae has less demanding nutrient requirments.


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## Lawrence Lee (Jul 17, 2004)

But when plants have accustomed to the carbon source, any variation to the dosing (or stopping Excel dosing altogether) will stimulate another new growth of BBA.

I use it by painting Excel with a brush onto affected leaves, and after that, keep tank conditions stable (read no water change after the algae killing work is done) so plants will find the equilibrium, adapt, grow and totally knock out the algae.


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## Grayum (Jun 14, 2006)

That is a really good idea, painting with a brush. Do you actually take them out of the tank to do this? (i'm assuming so)


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## Lawrence Lee (Jul 17, 2004)

Plants tied to driftwood and rock that can be taken out will be taken out and painted. Those rooted will be painted with water level lowered.


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## banderbe (Nov 17, 2005)

Lawrence Lee said:


> But when plants have accustomed to the carbon source, any variation to the dosing (or stopping Excel dosing altogether) will stimulate another new growth of BBA.


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That wasn't my experience. I used Excel for a few months, then stopped. No algae followed.


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## Lawrence Lee (Jul 17, 2004)

Lawrence Lee said:


> But when plants have * accustomed to the carbon source, any variation * to the dosing (or stopping Excel dosing altogether) will stimulate another new growth of BBA.


The point I wanted to make was Inconsistent (read Variation) of carbon availability to plants will result in the return of algae.

Algae grows when the carbon level is inconsistent or fluctuating. Examples are: inconsistently dosing Excel on some days and missing it on others; taking Excel off the dosing regimen when plants have gotten accustomed to that as an *only* source of carbon for a long time; inconsistent CO2 injection; even frequent water changing will cause algae for a non-CO2 injected NPT.

That is why I recommend using Excel as a form of "algaecide" by painting it onto algae infected leaves, (and not as a long term source of carbon). One can also use Hydrogen Peroxide as an algaecide in the same paint on manner described. But after the algae hsd been killed, it is important that the plants grow well to take over the niche vacated by the algae. This can be achieved only through consistency, as plants need a consistent environment to adapt to before growing.

That means minimal to no water changes in an NPT, and if you wish to dose anything, dose consistently.

Please don't misunderstand me into thinking that algae WILL come as the result of stopping Excel dosing as though it is a "withdrawal symptom"


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