# Seachem Flourish Excel



## Muso1981 (16 Mar 2021)

Hi everyone,

I've been adding Seachem Flourish Excel to my planted tank for for a couple of weeks daily and I'm not noticing any difference. I have stuck exactly to the recommended dose and I have a JBL CO2 reader which hasn't changed colour at all it remains dark blue. Do you think it would be safe to increase the dosage?


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## Mark Nicholls (16 Mar 2021)

Flourish Excel won't change the colour of a Dropchecker. It's more of an algaecide than a source of bioavailable carbon. The amount of Carbon released is TINY and WONT show up on a Dropchecker. It's made from glutaraldehyde which is extremely toxic if used at greater concentrations than recommended. Saying that, you CAN go upto double the stated dose before its totally toxic to life, HOWEVER there are many plants that won't tolerate excel (vallis and mosses for example) 
Excel appears to boost plant growth because it kills certain types of algae (especially beard algae). Once dead, the algae is no longer competing with plants for available nutrients therefore the plants show a slight improvement in growth. 
My personal opinion is its a great algaecide but is a very expensive and ineffective way of introducing carbon into the water. Even a DIY co2 unit pumps in much more! 
Hope this helps.


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## Muso1981 (16 Mar 2021)

Thanks Mark, that's really good to know. I have no algae so I think I will stop using it then. Is there a low tech way to increase CO2 into the water as I don't really want to be getting into gas canisters etc. 

Many thanks


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## Zeus. (16 Mar 2021)

Muso1981 said:


> Is there a low tech way to increase CO2 into the water



Having good surface agitation and a scum free water surface will keep the free CO2 optimal with atmospheric CO2, plus keep O2 levels up at night too. Fish do like a bit of surface current as well IMO


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## Libba (16 Mar 2021)

Muso1981 said:


> Thanks Mark, that's really good to know. I have no algae so I think I will stop using it then. Is there a low tech way to increase CO2 into the water as I don't really want to be getting into gas canisters etc.
> 
> Many thanks



Why do you feel that you need to increase your CO2?


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## ceg4048 (16 Mar 2021)

Mark Nicholls said:


> Excel appears to boost plant growth because it kills certain types of algae (especially beard algae).


Hello,
         Sorry, but this is not accurate. Although Excel and other glutaraldehyde products are toxic to some forms of algae many plants have a mechanism to internally degrade the  glutaraldehyde into CO2 or into a CO2 precursor. The exact mechanism is known only to a few, who, by contract agreement are not permitted to disclose. Compared to CO2 gas, the effective amount of CO2 is low, however it is high enough that one can actually raise CO2 loving plants using glutaraldehyde exclusively.


Mark Nicholls said:


> there are many plants that won't tolerate excel (vallis and mosses for example)


The plants that suffer toxicity are usually species such as liverworts and bladderworts. Toxicity is a function of concentration and there are many who report no damage to vallis or to certain mosses.


Mark Nicholls said:


> Once dead, the algae is no longer competing with plants for available nutrients therefore the plants show a slight improvement in growth.


This is also a famous myth, I'm afraid. Plants are never able to compete with algae at any time. Plants require thousands of times less nutrients than plants, which have large, complex infrastructure. This is like saying that elephants compete with mice for food.
Algae are very small, have very simple requirements and can thrive on nutrient concentration levels in the parts per billion. At these lean levels plants would be obliterated. Plants do not occupy the same biological space as algae.


Mark Nicholls said:


> is a very expensive and ineffective way of introducing carbon into the water. Even a DIY co2 unit pumps in much more!


Also not true. Expensive, yes but works well for smaller tanks and is much more effective than yeast based systems (if that's what you're referring to). As the tank size increases though the expense does provide diminishing returns. For the daring glutaraldehyde  can be purchase in bulk and diluted, reducing the cost, but I agree with you that the toxicity is something to be wary of.

Cheers,


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## Mark Nicholls (16 Mar 2021)

You have misunderstood several of my statements. 
Re: plants competing with algae. I am saying that glut kills the algae. Once the algae is dead, there are more nutrients available for the higher plants so they grow. 
Re: Company secrets: If its only known by a few people who are bound to secrecy, how do YOU know this? I would love to see the science behind your claim. 
Re: Plants melting. There are simply too many accounts of certain higher plants struggling with glut for it to be discounted.


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## ceg4048 (17 Mar 2021)

Mark Nicholls said:


> plants competing with algae. I am saying that glut kills the algae. Once the algae is dead, there are more nutrients available for the higher plants so they grow.


Hi Mark,
             No I have not misunderstood this statement. Yes, I agree that glut kills some algae but no, killing algae does not result in any significant amount of additional available nutrition because the amount of nutrition that algae will have been using is miniscule in comparison to the needs of higher plants. In fact, the amount of nutrition that algae use is on the order of 1/1000th to 1/10,000th of what plants use, so killing algae will only result in an increased nutrient availability on the order of 0.00001% to about 0.0000001% which makes no difference at all to the plant.


Mark Nicholls said:


> If its only known by a few people who are bound to secrecy, how do YOU know this? I would love to see the science behind your claim.


I know this because Seachem contracted Tom Barr to investigate the mechanism and to produce the resulting data. We asked him to disclose the information and he refused, citing the non-disclosure agreement. You'll never see the science behind my claim because it's locked up, however, you can prove the claim by simply raising plants in a glut environment and see the results for yourself. Alternatively, you can search the forum for glutaraldehyde  posts and see the results others have produced.


Mark Nicholls said:


> Plants melting. There are simply too many accounts of certain higher plants struggling with glut for it to be discounted.


Yes, I know. As I mentioned, toxicity is a function of the concentration level as well as the resistance of individual plants. I usually recommend against the use of glut if the tank has Vallis, however, others have dosed it and have avoided trouble as in the case of this thread Algae identification
There are other reports of success with glut with Vallis, but normally the poster limits the concentration. Just do a search for Vallis and you'll see examples. For my own part I've had no trouble with glut. You have to test these things for yourself and be willing to destroy your tank in order to determine the truth, not just report what others have said on random internet sites. The vast majority of plants we have access to are fine with glut, but some, such as what I mentioned suffer toxic effects.
FYI I have dosed up to 3X bottle recommendation (not with Vallis) and have had no problems with any stem plant. Here is a tank using gas and supplementing with Excel:





Also, I've had no negative effects with Xmas moss, but of course each hobbyist must check for themselves. I haven't tried it with every moss or with every plant, but those I have had in the tank were fine with Excel. One just has to be careful. Start with small amounts and progress from there. If you search the forum you'll find examples of tanks using Excel exclusively.


Cheers,


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## Mark Nicholls (17 Mar 2021)

You are forgetting that algae not only consumes liquid nutrients but for plants, the most important nutrient is LIGHT! IF a leaf has algae growing on it, yes a tiny amount of nutrient is used, BUT the algae 9n the leaves prevents the plants from photosynthesising as effectively! 50% or more of available light can be lost on a leaf surface with a good coating of algae. When the glut kills the algae and its then eaten, the available light is greatly increased, resulting in a growth spurt!


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## Libba (17 Mar 2021)

ceg4048 said:


> Hello,
> Sorry, but this is not accurate. Although Excel and other glutaraldehyde products are toxic to some forms of algae many plants have a mechanism to internally degrade the  glutaraldehyde into CO2 or into a CO2 precursor. The exact mechanism is known only to a few, who, by contract agreement are not permitted to disclose. Compared to CO2 gas, the effective amount of CO2 is low, however it is high enough that one can actually raise CO2 loving plants using glutaraldehyde exclusively.
> 
> The plants that suffer toxicity are usually species such as liverworts and bladderworts. Toxicity is a function of concentration and there are many who report no damage to vallis or to certain mosses.
> ...



Hey Clive,

I just have a couple of questions regarding this part of your post. When you say that plants cannot compete against algae, do you mean that in a general sense or specifically in regard to competing for nutrients? The reason that I ask is that the common advice I read from experienced aquarists is that the best defense against algae is a large biomass of healthy plants, and that healthy plants are very algae resistant. This would indicate that plants are competing against algae; whether it's competing for nutrients, light or just for physical space. What are your thoughts on this?

Cheers


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## ceg4048 (18 Mar 2021)

Libba said:


> Hey Clive,
> 
> I just have a couple of questions regarding this part of your post. When you say that plants cannot compete against algae, do you mean that in a general sense or specifically in regard to competing for nutrients? The reason that I ask is that the common advice I read from experienced aquarists is that the best defense against algae is a large biomass of healthy plants, and that healthy plants are very algae resistant. This would indicate that plants are competing against algae; whether it's competing for nutrients, light or just for physical space. What are your thoughts on this?
> 
> Cheers


Hi Libba,
             As it turns out, in just about every sense of the term, plants cannot compete with algae, _especially _when it comes to nutrients. Yes, I know, a lot of experienced hobbyists say that plants compete with algae on almost every website, but it's not because they understand the facts, it's because The Matrix told them what to think, and they then thought it. In other words, they read it somewhere from some source that failed to do any kind of research and simply hypothesized what was thought _should _be. In fact, many myths that proliferate today have nothing to do with science but instead have been handed down one source to another. Think about the popular myth that nutrients cause algae. how many websites and experienced hobbyists continue to purport this?

It should be obvious that algae are microscopic in size and mass and therefore their nutrient uptake can only be microscopic in volume and mass. When you have an algal bloom in the tank it seems as if the algae are everywhere, right? But if you were to scrape off every cell from every surface in the tank you'd see that the entire amount would be very small compared to the mass of the plants. 
Plants have nutrient reserves, so they can survive a blackout for some days. Algae do not have vast reserves of nutrition. They depend on the light to produce their food. That's why blackouts work in eradicating some species from the tank. That's why algae is so pervasive, because everyone thinks that more light is better and that it will enable plants to outcompete algae. 

Algal spores are everywhere in the tank and they even inhabit the biofilm covering the plant leaves. When the plant is in poor health their tissues begin to decay and they actually start to leach their internal chemistry into the water column, including nutrients. In a way, it's a sort of bleeding. Algal spores are right there at the site of the wound and can actually feed from the leeched products. They don't even have to compete because they are like vampires feeding from their victim.

In our tanks the relationship between algae and plants are that algae are the predators and plants are the prey, so yes, a healthy plant can resist their attacks, but prey do not compete for resources with the predators.

Cheers,


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## ceg4048 (18 Mar 2021)

Mark Nicholls said:


> You are forgetting that algae not only consumes liquid nutrients but for plants, the most important nutrient is LIGHT! IF a leaf has algae growing on it, yes a tiny amount of nutrient is used, BUT the algae 9n the leaves prevents the plants from photosynthesising as effectively! 50% or more of available light can be lost on a leaf surface with a good coating of algae. When the glut kills the algae and its then eaten, the available light is greatly increased, resulting in a growth spurt!


All of this may be true concerning the biofilm covering the leaf and in fact this is something that folks should pay more attention to when performing a water change. The biofilm covering the leaf should be cleaned if possible as the leaf itself ejects waste products which sit on the leaf surface and is an obstacle to CO2 and nutrients crossing the leaf membrane, however, just killing the algae does not remove it from the surface. As I mentioned, the improvement in growth is a direct result of the CO2 produced internally by the metabolism of the glutaraldehyde.

Cheers,


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