# Questions on Flourish Excel



## Fosty (Oct 17, 2003)

I have just started using Excel due to my lack of pacients for DIY co2 and my lack of money for pressurized co2. I haven't really found anything on how much to use and I never trust what they say on the bottle. So I have a few quick questions:

1: How often should I dose Excel if it is my primary carbon source?

2: For a high light tank, about how much should I use (per gallon)?

3: Can overdosing cause problems with fish or invertabrates?

I am definately using Excel on my 5.5 gallon as the primary carbon source, on my 20 gallon along with a bit of diy co2, and maybe as the primary carbon source on my 38 gallon until I can afford pressurized co2.


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## BSS (Sep 24, 2004)

Certainly not an expert in this area, but based on the fairly lengthy thread about using Excel to battle BBA, many folks have "over"dosed at 3-5+x the recommended amounts for upwards of 14 days with few reports of fish or related losses. Not sure that maps to a longer term plan for dosing Excel, but it's one data point.


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## Hypancistrus (Oct 28, 2004)

Flourish Excel is an isomer of a surgical disinfectant known as glutaraldehyde. An isomer is a compound that has the exact same number and type of atoms as another, but has a different molecular arrangement. Seachem has named the isomer "polycycloglutaracetal". It is less reactive than glutaraldehyde.

They also use it in in Paraguard (a medicine) and Stressguard (their slime coat product).

It is not recommended that the product be overdosed. There is no reason not to "trust" Seachem's printed instructions. Follow the instructions on the bottle.


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## Bert H (Dec 15, 2003)

I used to use it in a 10 gal tank and followed Seachems label. It worked ok, plants don't grow as fast as with co2. I used to dose every other day. If you have high lighting you might consider dosing daily.


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## snake (Jan 11, 2005)

Fosty,
I have used Excel along w/ DIY co2 in my discus 75 and 10 shrimp for about 4-6 mo. with excellent results. Good growth from plants and NO ALGAE.
I used just slightly more than directions call for. I dose with my daily fert schedule.
I plan on upgrading to pressurized soon but may continue use for the algae battling benefits alone. Before Excel and EI, I had BBA and bga out the wazoo. Now no algae, just bi monthly trims.
Dean


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## Fosty (Oct 17, 2003)

I was overdosing two times the amount they suggested, with no problems with fish, but I had been finding empty snail shells around and switched back to the suggested amount. I had no idea that Excel killed them (and I didn't mind the snail control), but with planning on adding shrimp I thought that I should play it safe. 



> There is no reason not to "trust" Seachem's printed instructions. Follow the instructions on the bottle.


I was just a little hesitant to go with their instructions because, well, I never have ended up using the amount Seachem gives with any of their other products. Seachem and other comercial fertilizer lines tend to write their instructions for the casual aquarist (which is fine), but I've found with a lot of their products they are having you underdose.

I think I'll stick to dosing about the suggested amout (rounding up to the nearest mL). 



Seachem said:


> Flourish Excel also has iron reducing properties which promote the ferrous state of iron (Fe+2), which is more easily utilized by plants than ferric iron (Fe+3).


Anyone know if this claim has any truth?


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## kimrin (Feb 21, 2005)

I killed plants and nearly killed my fish overdosing. Guess I read the directions a bit too literally. They suggest on your first application using 5ml per gallon and from there on using 5ml per 50 gallons several times a week. Problem was that they refer to using capfuls and I had bought a two liter bottle. The directions printed on it were for a smaller bottle with a smaller cap. Ended up dosing 10ml per gallon in all my tanks. It wiped out the vallisneria and anacharis practically overnight. Fish were gasping but I started some extra aeration and they made it through.
It was my own dumb mistake for using the cap measurement rather then paying attention to the actual ml's but it makes me wonder what people mean when they talk about overdosing it. I have to believe they mean overdosing in the sense of the daily applications ( 5ml per 50 gal), not the initial "first time" application.


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## shalu (Jan 16, 2003)

kimrin said:


> They suggest on your first application using 5ml per gallon and


actually 5ml per 10 gallon.



kimrin said:


> Ended up dosing 10ml per gallon in all my tanks.


Did you also mean "per 10 gallon"? Otherwise, it is 20x overdose of suggested initial dosage. Can the cap size be really 20x different? I don't think so, a 100ml cap is HUGE. When people say overdose, they are usually talking about 3x, no more than 5x.


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## Momotaro (Feb 21, 2003)

shalu said:


> When people say overdose, they are usually talking about 3x, no more than 5x.


I was going to make the same point.

When we talk of overdosing Excel the maximum overdose would be 3xs the recommendation. In fact many folks have great success when overdosing 2xs the recommended dosage. Going over 3xs is really taking a chance.

I would not do it.

Mike


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## kimrin (Feb 21, 2005)

you're exactly right, I did mean 5ml per 10 gallon. not per gallon. sorry.

it was still too much though. I could see doing 2x the 5ml per 50g, maybe even 3x. That would still be much less then what I added to a 55g tank which was 50ml. 

I was also told after the fact, that when adding larger amounts it's best to pull a container of tank water out and dissolve the dose in that first rather then adding directly to the tank.


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## livionakano (Aug 12, 2004)

Did any of you, Glutaraldehyde users, ever noticed a lowering, or even vanishing concentrations of NO3?
After noticed that, we tested even in a bucket of water, only with some KNO3, and after adding some Glutaraldehyde, concentration as lowered too much!
Could be a reaction from both, or a change in the testing parameters?

P.S. Not registered with Excel, just when using Glutaraldehyde 

Regards, 

Livio


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## Homer_Simpson (May 10, 2007)

Momotaro said:


> I was going to make the same point.
> 
> When we talk of overdosing Excel the maximum overdose would be 3xs the recommendation. In fact many folks have great success when overdosing 2xs the recommended dosage. Going over 3xs is really taking a chance.
> 
> ...


Agreed! 

I have never had issues with shrimp or otos in 5 gallon, 10 gallon, 3 gallon, or fish in 40 gallon with 2X the recommended dosage daily. However, dwarf aquatic frogs may be a different story. I cannot seem to keep a dwarf aquatic frog alive in a planted 5 gallon for more than 6 months tops(I have kept these frogs successfully in unplanted tanks with the longest one surviving 7 years so I am familiar with their requirements), and I have narrowed the issue down to the 2x dosing of Excel, but it is hard to say for sure as cause and effect is really difficult to prove. But is is likely that some species may be a lot more intolerant of 2x dosing of Excel. I am setting up another 1 gallon unplanted tank(currently fishless cycling it with ammonia and will spike ammonia levels again once cycled to build up sufficient nitrifying bacteria) and will be putting in 2 dwarf frogs once it is cycled. There will be no Excel dosing on this tank at all since there will be no plants. We will see what happens.


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## sewingalot (Oct 12, 2008)

Are there certain plants that are intolerant of dosing excel? I have heard Vals tend to melt, but do they come back eventually?


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## sp33drhno (Jan 8, 2009)

it seems like vals get used to excel eventually, at least this is what i've experienced. when i first put a large bunch of vals in my 55 gallon most of them melted, save a few leaves/blades. now that a few months have passed, they seem to be acclimating to the excel and are sending up nice green shoots.


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## 125gallon (Aug 28, 2008)

I have had some of my crypts melt some. I just cut back on my dosage and all seems well.


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