# Double Dosing excel for Algae



## CannaBrain (Oct 3, 2008)

At once.


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## Raymond S. (Dec 29, 2012)

I do mine at the same time.
The RCS seemed to have a reaction when I went from single to double doses but
since have been acting quite normal after I dose it.
Can't really say that I noticed any difference in the algae...but then what would it be like without it ?


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## Hoppy (Dec 24, 2005)

I believe the widely accepted "normal" dosage for Excel is now 2 ml per 10 gallons of water, every day, which is twice what it calls for on the bottle. But, don't use the 5 ml per 10 gallons of water starting dosage at any time.


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## schnebbles (Jan 10, 2015)

Thanks! I'll try it.


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## Beefy (Mar 6, 2015)

Hoppy said:


> But, don't use the 5 ml per 10 gallons of water starting dosage at any time.


That dose has worked great for me as part of the one-two punch.


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## schnebbles (Jan 10, 2015)

> don't use the 5 ml per 10 gallons of water starting dosage at any time/QUOTE]
> 
> not sure I understand quite what that means. I try to do it in the morning before lights on.


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## mattinmd (Aug 16, 2014)

schnebbles said:


> not sure I understand quite what that means. I try to do it in the morning before lights on.


Hoppy was making suggestions on dosage amounts, not time of day..

If you read the label, Seachem suggests two different dosage rates to be used at different time.

Seachem suggests starting off with a 5ml dose for every 10 gallons, and then 1ml per 10 gallons every day. They also suggest repeating 5ml per 10gallon dose rate after water changes.

Pretty much everyone here thinks that is nonsense... It is said that Excel breaks down after 24 hours. If that is true, doing a 5-times normal dose rate as a starter or after water changes is pointless. A 5x starter dose would only make sense if the product lasted for 5 days in the tank, but it doesn't.

TPT users generally dose 1-2ml per 10 gallons of tank every day, and skip the starter dose. I personally am at about 1.4ml/10 gallons (5ml a day in a 36 gallon tank.)


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## schnebbles (Jan 10, 2015)

OK got it. Thanks!


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## Hoppy (Dec 24, 2005)

mattinmd said:


> Hoppy was making suggestions on dosage amounts, not time of day..
> 
> If you read the label, Seachem suggests two different dosage rates to be used at different time.
> 
> ...


It's amazing what can be done by using a few more words!:hihi:


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## Beefy (Mar 6, 2015)

mattinmd said:


> Pretty much everyone here thinks that is nonsense... It is said that Excel breaks down after 24 hours.


Breaks down completely? Or is 24 hours the half-life? Or is 24 hours the time it takes for plants to take-up the product from the water column? Or is 24 hours the time it takes for the glutaraldehyde to oxidise to a still-usable five-chain carbon molecule, glutaric acid?

A lot of assumptions, but nobody with a mass spec......


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## mattinmd (Aug 16, 2014)

Beefy said:


> Breaks down completely? Or is 24 hours the half-life? Or is 24 hours the time it takes for plants to take-up the product from the water column? Or is 24 hours the time it takes for the glutaraldehyde to oxidise to a still-usable five-chain carbon molecule, glutaric acid?
> 
> A lot of assumptions, but nobody with a mass spec......


Yeah, that's why I used the term "It is said"... 

However, every time I've heard "it said", the assertion was that it broke down completely within 24 hours, and there was absolutely no carbon enhancing activity left...

I've even asked the question if anyone had any evidence as to which breakdown mechanisms are the prevalent ones in aquarium tanks... only crickets could be heard in response...

Clearly there's a lot we don't understand about glutaraldehyde in aquarium use.

edit:
Digging around in this thread:
http://www.plantedtank.net/forums/showthread.php?t=92707

I found a link to an article about glutaraldehyde breakdown in river water:

http://link.springer.com/article/10.1007%2Fs002440010248

It gives the half-life of glut as 10.6 hours in aerobic river water, 7.7 in anerobic river water. However, sterile water caused no appreciable breakdown except at extreme pH over 31 days.

So, it is reactions with organics and/or living organisms that cause the breakdown, but I think we all knew that.. the half-life numbers are new to me.

Assuming our tank water is anything like aerobic river water, then we should see a 10.6 hour half-life.. In actuality, our tanks may be considerably more bio-active than river water, as the density of fish and bacteria is going to be higher. 

Regardless, sticking with a 10.6 hour half-live would suggest that after 24 hours we are decayed by more than 2 half-lives, and about 20.8% of the original dose remains in the water after 24 hours. However, that's only the breakdown of gultaraldehyde into glutaric acid..

According to this MSDS:
http://www.inchem.org/documents/sids/sids/111308.pdf

Which quotes the same 10.6 hour half-life for glut to glutaric acid, but also says the glutaric acid is completely metabolized within 48 hours...

So, perhaps 48 hours is a better life-span for the CO2 producing effects of Glutaraldehyde/excel/etc than 24 hours...


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## Hoppy (Dec 24, 2005)

If I remember correctly Seachem is the originator of the statement that Excel breaks down in about a day. It would be interesting to know how that happens, but apparently it is a fact that it does happen.

Since Seachem says to dose 5 ml per 10 gallons after a big water change it must be true that at that dosage Excel does not harm the fish or plants. That suggests that if you were to dose at that rate every day or two you would not harm the fish or plants. And, I know some people have done it. However, at high dosages like that I know that Vals do die back, but most eventually resume growing later. I haven't tried it since I like the results I get with Metricide, a glutaraldehyde product that works as an Excel substitute, when I dose at 2 ml per 10 gallons. (Actually about 10 ml per about 60 gallons of water.)


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## schnebbles (Jan 10, 2015)

I'm going to look that metricide up for next time.


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## Kntry (Dec 26, 2013)

Can you use Excel in a tank with CO2 to get rid of algae?


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## Beefy (Mar 6, 2015)

Yes.


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## Hoppy (Dec 24, 2005)

schnebbles said:


> I'm going to look that metricide up for next time.


You can get it through Amazon at a good price. Some of their feedback is from planted tank guys.


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## mattinmd (Aug 16, 2014)

Just be aware that metricide is slightly more concentrated than Excel (2.6% vs 2%), so you end up dosing about 3/4 (76.9%) of what you would with Excel..

Some posts out there seem to suggest Excel is 1.7% (resulting in having to dose 65% as much metricide), but their MSDS says 2%...
http://www.seachem.com/support/MSDS/FlourishExcel.doc.pdf


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## schnebbles (Jan 10, 2015)

Thanks for that! I'm keeping this thread so I have all this when I need it.


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