# How can plants outcompete algae for nutrients? this makes no sense to me.



## ER9 (Aug 2, 2008)

from what iv'e come to understand, if i understood what iv'e read so far...tom barr suggests that elevated nutrients dont cause algae, and the premise behing his ei method is to give the plants all the nutrients they can use...and more. if i am correct in my interpretation...how can plants outcompete algae for nutrients or vice versa? isn't there plenty to go around for both the plants and algae? if this is the case then why do folks keep saying to add more plants to soak up the excess nutrients to control algae? i'm thoroughly confused. 

please bear with me in my inexperience...i'm really trying to come to grips with algae and what really causes it.

if tom barr is in fact correct then its something other than excess nutrients responsible for algae. i would assume the next logical place to look for 'most' major algae issues is nutrient imbalance, in regard to what the variety of plants in a particular aquarium are using up, or what imbalances are being created in any particular aquarium. after all every aquarium is an individual micro climate/environment. in this light the 50% 'reset' water change starts to make sense to me. you never let your tank 'bottom out' so to speak on any nutrients. even if there are conditions present that could cause an imbalance over time.


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## Naja002 (Oct 12, 2005)

Aaaaaaaah, Very good. :thumbsup: It doesn't make much sense, does it? :thumbsup: Let me try to explain my current understanding in layman's terms.....I haven't quite sorted out all of the details yet, but I think that I can help clear somethings up for you.



ER9 said:


> from what iv'e come to understand, if i understood what iv'e read so far...tom barr suggests that elevated nutrients dont cause algae, and the premise behing his ei method is to give the plants all the nutrients they can use...and more.


Correct. :thumbsup:




ER9 said:


> if i am correct in my interpretation...how can plants outcompete algae for nutrients or vice versa? isn't there plenty to go around for both the plants and algae?



Yes, there is plenty to go around...that is the point of EI: to prevent limitations (shortages).





ER9 said:


> if this is the case then why do folks keep saying to add more plants to soak up the excess nutrients to control algae? i'm thoroughly confused.


Because they really don't understand generally and what the original purpose was of that recommendation. There are situations when more plants are better (dead rotting fish), but once a system is cycled....it's not such a big deal any more. Now, when a tank is first setup it's good (but not necessary) to have a bunch of plants. Why? Ammonia. NH3/NH4. Algae loves ammonia (well, some anyway.) But, from what I understand--algae really likes it at low levels. Algae start to uptake at ~0.0-0.5ppm, but plants don't really kick in until ~0.5-2.0ppm. So, during a cycle ammonia is high and the plants really love it. I think, but am not sure, that when production of ammonia is high enough...that plants will switch over to it for their primary N source. Which I believe helps keep ammonia very low. Seems that this would _*favor*_ algae. Well, yes it would. But more plants will absorb more ammonia possibly using it up as quickly as it's being produced. The theory is that you don't need to "cycle" a planted tank--meaning: add water, add plants, add fish. And if you think about it: algae blooms are most common during start up--meaning the first several months until the substrate and system overall have an opportunity to "mature".

However, down the road things are going great, but for some reason there's a dead fish rotting somewhere in the tank--that fish is kicking out ammonia. Probably reasonably low level--enough to favor algae and not plants, but also enough to require a slight increase in the bacterial colony. That increase is going to take a little bit of time. In the interm--everything may reach that sweet spot that tells certain algae spores to germinate. Bam! You have algae. Again, it still goes back to "cycling" (the bacterial colony) and ammonia.

But generally speaking, the recommendation to "stuff it with plants" was a start up thing that got extended to fix every algae problem under the sun and now is just a blind recommendation. Parroting.




ER9 said:


> please bear with me in my inexperience...i'm really trying to come to grips with algae and what really causes it.


No sweat. Great question. :thumbsup:



ER9 said:


> if tom barr is in fact correct then its something other than excess nutrients responsible for algae.


Right, and Tom says that. That is the whole intent of EI after all. That and no testing required.




ER9 said:


> i would assume the next logical place to look for 'most' major algae issues is nutrient imbalance, in regard to what the variety of plants in a particular aquarium are using up, or what imbalances are being created in any particular aquarium.


This one I have to stumble around on. Nutrient imbalances generally cause nutrient deficiencies in the plants. However, that weakens growth and the overall healthy/vitality of the plant(s)--which does favor algae in one way or another and to one degree or another.

In some respects you are right, but I think that your understanding can be taken too far (across the board) too easily. One example is BBA....loves low C02 conditions. C02 is considered a nutrients, so with that example you are right. But what causes GSA? Some say low P04 and/or low C02 and/or both. Is that right? Well, at this point I personally tend to believe that it is, but I'm not sure. So, you are probably right. Hair algae and clado.....people believe that excess Iron causes one or both of these....I don't believe that. I don't think we really know at this point, but here's what I'm thinking after some experience and reading around on it a while back: Excess Fe doesn't cause the algae--it causes the limitation (shortage) of some other nutrient (probably a different micro) and that some how creates the environment for one or both (depending upon what ya believe) of those particular types of spores to germinate. If so, then again...you would be right.

However, I think we understand that green water is usually caused by ammonia from say disturbing the substrate. So, in that case...it's not really what we would consider a "nutrient" imbalance.

But, I think the bottomline is: We really don't understand yet what exactly causes many of these algae types to germinate. A major source of frustration for me. I don't have many algae issues, but it really sux trying to put all of the pieces of this big planted tank puzzle together--when they are not all there.




ER9 said:


> after all every aquarium is an individual micro climate/environment. in this light the 50% 'reset' water change starts to make sense to me. you never let your tank 'bottom out' so to speak on any nutrients. even if there are conditions present that could cause an imbalance over time.



It's hard to understand your perspective on this clearly--the way it's presented/worded.

The 50% WC is to prevent excess build up of nutrients. Dosing in slight excess of what the plants can use is to prevent the "bottoming out". So, we dose in slight excess to prevent limitations/imbablances and do the 50% WC to prevent long-term buildup.


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## Hoppy (Dec 24, 2005)

Again quoting from Tom Barr, but taking great liberties to paraphrase what he said because I never remember this stuff verbatim, algae compete with plants for light, not nutrients. When algae cover a plant leaf, it is taking away the light the plant needs. But, when plants grow to the top of the aquarium, or natural body of water, they are taking away the light the algae needs. Algae survive by growing rapidly when conditions are good enough for them, but not yet good enough for plants, giving them first dibs on the light. If we don't allow conditions to ever be not good enough for the plants, many/most/all(?)algae will just not start their growth cycle - that is the very well cared for aquarium we so enjoy seeing photos of here.


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## ER9 (Aug 2, 2008)

Naja002 said:


> Because they really don't understand generally and what the original purpose was of that recommendation. There are situations when more plants are better (dead rotting fish), but once a system is cycled....it's not such a big deal any more. Now, when a tank is first setup it's good (but not necessary) to have a bunch of plants. Why? Ammonia. NH3/NH4. Algae loves ammonia (well, some anyway.) But, from what I understand--algae really likes it at low levels. Algae start to uptake at ~0.0-0.5ppm, but plants don't really kick in until ~0.5-2.0ppm. So, during a cycle ammonia is high and the plants really love it. I think, but am not sure, that when production of ammonia is high enough...that plants will switch over to it for their primary N source. Which I believe helps keep ammonia very low. Seems that this would _*favor*_ algae. Well, yes it would. But more plants will absorb more ammonia possibly using it up as quickly as it's being produced. The theory is that you don't need to "cycle" a planted tank--meaning: add water, add plants, add fish. And if you think about it: algae blooms are most common during start up--meaning the first several months until the substrate and system overall have an opportunity to "mature".
> 
> However, down the road things are going great, but for some reason there's a dead fish rotting somewhere in the tank--that fish is kicking out ammonia. Probably reasonably low level--enough to favor algae and not plants, but also enough to require a slight increase in the bacterial colony. That increase is going to take a little bit of time. In the interm--everything may reach that sweet spot that tells certain algae spores to germinate. Bam! You have algae. Again, it still goes back to "cycling" (the bacterial colony) and ammonia.


i had to stop reading and respond right here. this point about ammonia you are bringing up really intrigues me. 

i didn't realize this about low levels of ammonia in regards to algae. is it theoretically possible then to add another filter or a larger one, or in some way increase the beneficial bacteria in an individual aquarium so they would take care of any low level ammonia the plants cant use? 

it makes me think that a tank with high light levels and filled with slow growing plants, possibly with inadequate filtration (read beneficial bacteria) is doomed a painfull life of algae outbreaks. could this be what is happening when people warn cautiously that adding higher wattage light and that it will cause algae outbreaks? wether they realize it or not? it would make sense to me to be so. 

actually ok now it makes sense then....if i'm beggining to see the light...i guess the faster growing stem plants, or adding more plants doesn't "soak up excess nutrients" per se but rather soaks up/neutralizes low levels of ammonia and thats why it probably works.


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## ER9 (Aug 2, 2008)

Naja002 said:


> It's hard to understand your perspective on this clearly--the way it's presented/worded.
> 
> The 50% WC is to prevent excess build up of nutrients. Dosing in slight excess of what the plants can use is to prevent the "bottoming out". So, we dose in slight excess to prevent limitations/imbablances and do the 50% WC to prevent long-term buildup.


ahhh...ok i get it. you are correct. my thought process was backwards on this one.


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## ER9 (Aug 2, 2008)

Naja002 said:


> This one I have to stumble around on. Nutrient imbalances generally cause nutrient deficiencies in the plants. However, that weakens growth and the overall healthy/vitality of the plant(s)--which does favor algae in one way or another and to one degree or another.
> 
> In some respects you are right, but I think that your understanding can be taken too far (across the board) too easily. One example is BBA....loves low C02 conditions. C02 is considered a nutrients, so with that example you are right. But what causes GSA? Some say low P04 and/or low C02 and/or both. Is that right? Well, at this point I personally tend to believe that it is, but I'm not sure. So, you are probably right. Hair algae and clado.....people believe that excess Iron causes one or both of these....I don't believe that. I don't think we really know at this point, but here's what I'm thinking after some experience and reading around on it a while back: Excess Fe doesn't cause the algae--it causes the limitation (shortage) of some other nutrient (probably a different micro) and that some how creates the environment for one or both (depending upon what ya believe) of those particular types of spores to germinate. If so, then again...you would be right.
> 
> ...


actually this makes more sense now considering what hoppy just mentioned below. again if i'm interpreting this all correctly. 

if imbalances are created via nutrients, co2, whatever then plants stall their growth as you mentioned in a previous post. if this happens then algae would win competition for light and flourish. this, it think would be exaserbated by higher light conditions.

its starting to make me wonder if most BGA outbreaks (my current algae battle) are really a lack of nutrients in general. especially since BGA is capable of synthasizing its own no3. in this condition (lack of available nutrients...especially NO3 which is responsible for fast, vegetative growth) plants suffer, not growing. BGA has most of what it needs to grow and makes what it doesn't. the result is BGA flourishes and plants dont. this is really interesting to me because one of the factors present when my BGA outbreak started was that i had just cut way back on my fertilizer regimen.


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## mistergreen (Dec 9, 2006)

plants inhibit algae with chemicals also. If you have healthy plants, they do a good job of inhibiting algae growth.


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## mistergreen (Dec 9, 2006)

ER9 said:


> its starting to make me wonder if most BGA outbreaks (my current algae battle) are really a lack of nutrients in general. especially since BGA is capable of synthasizing its own no3. in this condition (lack of available nutrients...especially NO3 which is responsible for fast, vegetative growth) plants suffer, not growing. BGA has most of what it needs to grow and makes what it doesn't. the result is BGA flourishes and plants dont. this is really interesting to me because one of the factors present when my BGA outbreak started was that i had just cut way back on my fertilizer regimen.


ehhh, I wouldn't assume that... plants and algae can and do grow in the same nutrient 'balanced' environment. Ask any experienced aquarist here 
It's puzzling sometimes when everything seems balanced but yet the tank has an algae outbreak.


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## @[email protected] (Oct 24, 2007)

mistergreen said:


> plants inhibit algae with chemicals also. If you have healthy plants, they do a good job of inhibiting algae growth.


im not sure how much this plays in in a high-tech tank. aleopathy may work on inhibiting growth on the plants' leaves themselves as they constantly pump out the aleochemicals, but they wouldnt build up in any sufficient quantity in the water to inhibit algae growth all over in a tank, with weekly 50% water changes (reccomended in EI). 

i know i am yet to find an explaination to make me understand how you can have a lot of CO2 and light (good for photosynthesis of either plants or algae), and plenty of nutrients in the water column, and yet the algae isnt getting any for some reason.


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## ER9 (Aug 2, 2008)

mistergreen said:


> ehhh, I wouldn't assume that... plants and algae can and do grow in the same nutrient 'balanced' environment. Ask any experienced aquarist here
> It's puzzling sometimes when everything seems balanced but yet the tank has an algae outbreak.


 i get the irony but my reasoning was that i was just reading on t. barr's site that algae can grow in _extremely_ low levels of nutrients provided from decaying plants etc....that might not be enough for the plants. in the case of BGA...if no3 (required for most vegetative growth) is very, very low, plant growth would almost come to a hault....as chlorosis would crop up and the plant eventually die. in this maybe oversimplified example, BGA could make its own NO3 (probably explains where the recomendation to add NO3 to cure bga came from) and continue to flourish uninhibited. the reason why adding more no3 probably doesn't work as a fix alot of time (it did absolutely nothing for me) is that its a symptom of a greater macro problem/deficiency of nutrients in general, no3 being just one of them.


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## Naja002 (Oct 12, 2005)

ER9 said:


> i didn't realize this about low levels of ammonia in regards to algae. is it theoretically possible then to add another filter or a larger one, or in some way increase the beneficial bacteria in an individual aquarium so they would take care of any low level ammonia the plants cant use?


No. The bacteria are fed by the NH3/NH4 and N02, respectively. So, there is only going to be enough bacteria as there is food to feed them. Once the tank is cycled--the bacteria has reach equilibruim with it's food supply (NH3/NH4 and N02). Adding a source of NH3/4 or N02 will cause a mini cycle. If ya add a bunch of fish--it will cause a major cycle. Removing a part of the NH3/4 (say a bunch of fish) will cause the bacterial colony to reduce as some of it starves...until it reaches the new equilibrium.

Short-term-Yes. Long-term-No.




ER9 said:


> it makes me think that a tank with high light levels and filled with slow growing plants, possibly with inadequate filtration (read beneficial bacteria) is doomed a painfull life of algae outbreaks.


Again, this is only until the bacterial colony reaches equilibrium.



ER9 said:


> could this be what is happening when people warn cautiously that adding higher wattage light and that it will cause algae outbreaks? wether they realize it or not? it would make sense to me to be so.


It's nice to make excuses for people and give the benefit of the doubt....but most of it is parroting. They understand that low light reduces algae, but not necessarily why. Some understand further that light is the driving force, but don't understand how it actually drives everything and how it all plays out. Don't get me wrong--we all want to participate. We all want to further our knowledge/understanding by trying to help others out. But much of it is still parroting. And that's cool for some things and people that have not been around this for very long. But sadly--they are they exception, not the rule.

Higher light drives everything faster....everything. Plain and simple. Growth is faster, so more nutrients overall are consumed....offering a greater possibility for a shortage. Nutrient deficiencies show up faster....and go away--once fixed--faster. But the higher light favors algae also. So, when something gets out of whack--it doesn't take long for algae to show up and prosper. That's the intent of EI: Provide more then the plants can possibly use and thereby prevent limitations....preventing deficiencies and algae. Maintaining a tank properly will help prevent any excess ammonia from being available to trigger algae germination.

But, Yes, people's intention's are good, but the road to hell is paved with the *Best* of intentions....:thumbsup:




ER9 said:


> actually ok now it makes sense then....if i'm beggining to see the light...i guess the faster growing stem plants, or adding more plants doesn't "soak up excess nutrients" per se but rather soaks up/neutralizes low levels of ammonia and thats why it probably works.



Right--more or less--in a cycling (higher NH3/4) state. Otherwise, the bacteria mainly deal with the NH3/4. One problem is that the ammonia has to get from it's source to the bacteria. The bacteria are all over the system--glass, substrate, plants, filter, tubing, etc, etc, etc., so as long as the bactera and the NH3/4 and N02 are at equlibrium...life is good as far as ammonia goes. But, as I understand it, plants adapt to whatever is abundant. Generally that is N03. It takes time and energy for a plant to "change-over" to processing a nutrient in different form (NH3/4, N02, N03--are all N). So, and I may be wrong here....once a plant is setup to abosrb N03 as it's primary source of N....it's somewhat reluctant to change over at the first signaling of NH3/4/N02, so those have an opportunity to build and trigger algae germination. <<<Now I know/believe that that is not 100% accurate, but that's my current generally understanding.


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## Naja002 (Oct 12, 2005)

Hoppy said:


> Again quoting from Tom Barr, but taking great liberties to paraphrase what he said because I never remember this stuff verbatim, algae compete with plants for light, not nutrients. When algae cover a plant leaf, it is taking away the light the plant needs. But, when plants grow to the top of the aquarium, or natural body of water, they are taking away the light the algae needs. Algae survive by growing rapidly when conditions are good enough for them, but not yet good enough for plants, giving them first dibs on the light. If we don't allow conditions to ever be not good enough for the plants, many/most/all(?)algae will just not start their growth cycle - that is the very well cared for aquarium we so enjoy seeing photos of here.


Competing for light, not nutrients actually makes sense. A lot of thread, fuzz, staghorn, BBA, GSA, etc are in high light conditions and seem to pick places (Up toward the tops of the plants) that favor light to themselves (algae).

But the trick is germination--whatever the necessary triggers are for a specific type of algae--those conditions have to be available long enough to trigger the spores to germinate. I may be wrong, but once germination occurs--the algae become considerably more adaptable.

But there's something here about algae and slow growers, and I'm wondering if it has to do with the specific conditions within the Prandtl boundry.


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## Naja002 (Oct 12, 2005)

ER9 said:


> i get the irony but my reasoning was that i was just reading on t. barr's site that algae can grow in _extremely_ low levels of nutrients provided from decaying plants etc....that might not be enough for the plants. in the case of BGA...if no3 (required for most vegetative growth) is very, very low, plant growth would almost come to a hault....as chlorosis would crop up and the plant eventually die. in this maybe oversimplified example, BGA could make its own NO3 (probably explains where the recomendation to add NO3 to cure bga came from) and continue to flourish uninhibited. the reason why adding more no3 probably doesn't work as a fix alot of time (it did absolutely nothing for me) is that its a symptom of a greater macro problem/deficiency of nutrients in general, no3 being just one of them.


Or some other problem. Sometimes BGA is linked with inadequate flow. Sometimes, in an otherwise healthy tank, BGA can be seen between the glass and the substrate--but it doesn't prosper or spread. Why? That is the question. What is it about that area that is beneficial to BGA--yet keeps it contained to that area only? I don't have that answer.


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## mistergreen (Dec 9, 2006)

Naja002 said:


> It takes time and energy for a plant to "change-over" to processing a nutrient in different form (NH3/4, N02, N03--are all N). So, and I may be wrong here....once a plant is setup to abosrb N03 as it's primary source of N....it's somewhat reluctant to change over at the first signaling of NH3/4/N02, so those have an opportunity to build and trigger algae germination. <<<Now I know/believe that that is not 100% accurate, but that's my current generally understanding.


nope. plants prefer what's most available, NH4+ or NO3. However, they prefer NH4... When plants take in NO3, it takes energy to for it to convert it back to NH4, which it needs for N. With NH4 from the environment, it doesn't need extra energy for it to be usable.


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## Naja002 (Oct 12, 2005)

@[email protected] said:


> i know i am yet to find an explaination to make me understand how you can have a lot of CO2 and light (good for photosynthesis of either plants or algae), and plenty of nutrients in the water column, and yet the algae isnt getting any for some reason.


Until conditions are right--the algae spores will remain dormant and not germinate--that's why you don't see algae. The spores are there--they are just dormant. Waiting for the right conditions...those conditions "trigger" or signal the spores to germinate....


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## Naja002 (Oct 12, 2005)

mistergreen said:


> nope. plants prefer what's most available, NH4+ or NO3. However, they prefer NH4... When plants take in NO3, it take energy to for it to convert it back to NH4, which it needs for N.


Maybe I'm not understanding your post, but I think we agree. Yes, plants do prefer NH3/4, but as you say--it takes energy to switch back and forth, so once they are setup to uptake N03....they are somewhat reluctant to switch back to NH3/4 just because a little bit has become available. If I understood things correctly, that's why plants don't really focus on NH3/4 until ~0.5ppm, because N03 is generally more abundant and uptaking NH3/4 requires a switch....This low NH3/4 level niche is something that some algae have adapted to take advantage of....


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## @[email protected] (Oct 24, 2007)

Naja002 said:


> Until conditions are right--the algae spores will remain dormant and not germinate--that's why you don't see algae. The spores are there--they are just dormant. Waiting for the right conditions...those conditions "trigger" or signal the spores to germinate....


really?
so then the plants arent truely outcompeting the algae, as much as we are keeping the conditions unsuitable for spore germination. 
it fits.
but what i dont get is why did algae evolve this way? if there is plenty of N, and P, and K, and micros that the algae can use to grow, why would it evolve to not do so?
to me this would only make sense the BGA, since it thrives in environments with no N, where it has no competition at all. but its not an algae (kingdom protista), but actually the creature cyanobacteria (kingdom bacteria/eubactaria), and can fix N2. 
bacteria dont have spores do they? so then the one i see this making sense (according to evolution, that is), it doesnt.



> Maybe I'm not understanding your post, but I think we agree. Yes, plants do prefer NH3/4, but as you say--it takes energy to switch back and forth, so once they are setup to uptake N03....they are somewhat reluctant to switch back to NH3/4 just because a little bit has become available. If I understood things correctly, that's why plants don't really focus on NH3/4 until ~0.5ppm, because N03 is generally more abundant and uptaking NH3/4 requires a switch....This low NH3/4 level niche is something that some algae have adapted to take advantage of....


thats not how i understand the post.
i think he is saying that plants organic chemistry needs N bound to Hs in the final product, so they have to take energy to convert NO3 back to NH3. 
you on the other hand, are talking more about plants taking energy to switch between what compound they assimilate for their N. 

so if i understand you 2 right, you are saying to different things. and i think both are right. plants would preffer NH3 to NO3 for amino acid production if nothing else. idk about other compounds though, but it would be likely.
but they probably use protein channels in their cell walls and cell membranes to bring the NH3 and NO3 into their cells. and they need to use energy to make the other protien, and they might only maintain on at a time, since why maintain both, if the other isnt doing anything?


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## Naja002 (Oct 12, 2005)

@[email protected] said:


> really?
> so then the plants arent truely outcompeting the algae, as much as we are keeping the conditions unsuitable for spore germination.
> it fits.


Yes, it does. :thumbsup: That's why I've made comments in the past about "introducing" algae to our tanks....and it suddenly taking off and being impossible to get rid of. "Introduction" may apply more so to germinated spores (algae), but I don't think it applies to ungerminated spores. Our tanks are loaded with algae spores--and they will stay spores until the triggers are there to trigger their germination. Just because someone doesn't have any algae--does not mean that the spores are not there.



@[email protected] said:


> but what i dont get is why did algae evolve this way? if there is plenty of N, and P, and K, and micros that the algae can use to grow, why would it evolve to not do so?


There are plenty of niche environments and examples of life that take advantage of it in various ways. At least some jellyfish "offspring" will form pods (?) on the ocean floor. They'll sit in this state for up to 50yrs or more until one or more triggers signal their emergence--then there's a jellyfish bloom. It's just about long-term survival of the species...the genes.

It's the same with a plant seed. I can put it in my cabinet--and it won't germinate....but if I give it the proper triggers: soil, moisture, etc...it will. Some seeds lose their ability after a while. Some won't germinate unless the proper triggers include a cold spell (winter).....so, unless I put them in the freezer for a while...they won't germinate, because they were not given all the proper triggers.




@[email protected] said:


> to me this would only make sense the BGA, since it thrives in environments with no N, where it has no competition at all. but its not an algae (kingdom protista), but actually the creature cyanobacteria (kingdom bacteria/eubactaria), and can fix N2.
> bacteria dont have spores do they? so then the one i see this making sense (according to evolution, that is), it doesnt.


No they don't have spores, but some can go dormant. The bacteria in Seachem's Stability is an example of that. And the reason BGA grows in the substrate against the glass is, I believe, simply because there is very little flow in that particular microenvironment--if it tries to expand beyond that....it finds a much less friendly environment. Our tanks might be a microenvironment--but it has microenvironments within it also. So, the presence of BGA against the substrate/glass indicates that when conditions are right--bacteria/spores will come out of dormancy, but if conditions are not right elsewhere--it will restrict itself to an adequate environment.





@[email protected] said:


> thats not how i understand the post.
> i think he is saying that plants organic chemistry needs N bound to Hs in the final product, so they have to take energy to convert NO3 back to NH3.
> you on the other hand, are talking more about plants taking energy to switch between what compound they assimilate for their N.


I agree--we are saying different things, but agree on certain points. However, I no longer agree that our plants prefer NH4. They only prefer NH4 if it is available before N03 becomes abundant.




plantbrain said:


> The graph shows that NO3, not NH4 is preferred *under our plant tank conditions.*





plantbrain said:


> So the preference, as defined by _uptake rates_, suggest under aquarium conditions, NO3 is _preferred_.



Take a read through this and follow/read the 2 links also:

ammonia vs nitrate 


Apparently, the assumption is from the terrestrial plant world and applied to the aquatic plant world. Tom breaks down why plants prefer N03--*in our tank conditions.*




@[email protected] said:


> so if i understand you 2 right, you are saying to different things. and i think both are right. plants would prefer NH3 to NO3 for amino acid production if nothing else. idk about other compounds though, but it would be likely.
> but they probably use protein channels in their cell walls and cell membranes to bring the NH3 and NO3 into their cells. and they need to use energy to make the other protien, and they might only maintain on at a time, since why maintain both, if the other isnt doing anything?


We are saying 2 different things. But aquatic plants do not prefer NH4 after N03 becomes abundant:




plantbrain said:


> It is not until you get near 0.5ppm of NH4 that the rate of uptake is nearly = to that of NO3 uptake.


Aquatic plants only prefer NH4 until N03 becomes abundant. I think Tom explains that pretty well. Now, I don't claim to understand the details of what plants use to process NH4 v N03, but from what I understand--there is a switch involved. If there is not enough NH4--the plant won't switch....or at least greatly increase uptake.


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## Hoppy (Dec 24, 2005)

I think we have to keep in mind that algae have been on earth for eons, always evolving to better survive. This means any algae we see are algae that evolved not to live in an aquarium but to survive in natural bodies of water. Like all living things algae need to complete a life cycle in order to reproduce, and continue the existence of their species. Given the advantages plants have for taking light away from algae, algae must have evolved to utilize periods when plants are at a disadvantage, like when it has been too cold for plants to grow well, or when storms have flooded the waterway and washed away most of the plants, or when plants have ended their own life cycle and are decaying in the water, etc. Two things that occur during those periods are fluctuating CO2 in the water and ammonia surges in the water. Perhaps that is why either of those conditions starts algae growth in our tanks.


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## ER9 (Aug 2, 2008)

Hoppy said:


> I think we have to keep in mind that algae have been on earth for eons, always evolving to better survive. This means any algae we see are algae that evolved not to live in an aquarium but to survive in natural bodies of water. Like all living things algae need to complete a life cycle in order to reproduce, and continue the existence of their species. Given the advantages plants have for taking light away from algae, algae must have evolved to utilize periods when plants are at a disadvantage, like when it has been too cold for plants to grow well, or when storms have flooded the waterway and washed away most of the plants, or when plants have ended their own life cycle and are decaying in the water, etc. Two things that occur during those periods are fluctuating CO2 in the water and ammonia surges in the water. Perhaps that is why either of those conditions starts algae growth in our tanks.


we've talked about ammonia but its intereseting to read just how muchTom Barr stresses CO2 as a potential cause/trigger. i really didn't think it played such a potential large roll.


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## Homer_Simpson (May 10, 2007)

In a low light, low tech setup with no c02 injection, you would be hard pressed to find algae. And I have seen this with my own 2 eyes. Even when I had dead fish in the low tech that I did not find, any potential ammonia spikes did not trigger an algae outbreak. Hell, maybe I am just lucky, but I have yet to even seen Blue Green Algae form in my low tech, low light tanks. Personally based on what I have witnessed and seen, I am not saying that inconsistent c02 levels and ammonia spikes may not play a role in high light tanks, but they do not apply to low tech tanks, at least IME.

Another thing that I find interesting is that when I first set up planted tanks, there is often zero algae. Diatom algae is the only one that appears, but this also occurs in unplanted tanks so is not due to something particular with planted tanks IMHO. What happens over time, is that algae appears to materialize. To further add to the confusion, in some cases I have seen the opposite happen. The tank developed algae quickly at startup, but then as the tank matured it disappeared. I have also set up tanks, where all things being equal with respect to setup, some tanks developed algae while others remained algae free. 

For me these things raise more questions than answers.


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## Naja002 (Oct 12, 2005)

Right, and C02 is considered a nutrient, so we are still at the point of no limitations/shortages. But C02 is hard to control and ceratianly harder then the other variables (light/macro/micros). So, Tom has had a long battle trying to get people to understand/accept how not limiting C02 plays a major role.


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## plantbrain (Dec 15, 2003)

mistergreen said:


> plants inhibit algae with chemicals also. If you have healthy plants, they do a good job of inhibiting algae growth.


Naw they don't.
You need to offer support for this, it's never bene shown ever in any live system(eg not extracts of plants in little test wells etc) to date............

Ole and myself have lamblasted such claims from hobbyists, and the speculation that Diana Walstad made. You'd lose on virtually most every point to show support for this one.

Wishful thinking if more the reason why folks keep bring this one up over and over.

Rather than thinking about plants and algae in equal terms, they are radically different in respects to their *sizes and life histories. *I've mentioned this a dozen or more times here and many other places.

How many plants grow and reproduce in your aquariums sexually?
Virtually none. 

Algae?
Every one of them.

Think that changes things?
Yes.

How?
Well, the spores(instead of "seeds" in vascular seed plants), need some "germination signal".

They are not on equal terms nor is an aquarium entirely a homogenous place.
Plants are already there, there's no germination for them. This is not true for algae.

Algae spores will wait till there's a good chance for them to comple a life cycle. That is why they bloom.

Aquatic plants when growing well and not limited etc, modify the system, the plants define it, not the nutrients.

Size makes a huge difference as well, something the size of a single cell has no issues for CO2, a large massive Billion/trillion cell plant does. Algae are not CO2 limited, plants are. Big difference there. Also, the demands for a algae bloom are microscopic compared to the demands of the plants, a large bloom in an aquarium is only perhaps 500 milligrams of dry weight biomass, the plants might be 500 grams, 1000X more.

Uptake rates are also very different, algae max out at very very low levels, say 10 ppb for PO4, plants maybe 50ppb, and so on, this is true with macro algae vs microalgae.

But the bottom line for stable systems is prevention of germination of algae spores. Which is pretty easy to do if you take care of the plants.

The spores/algae appear to "know" or sense if there's someone else growing and doing well there. This has little to do with allelopathy, as it works with all 300-400 species of aquatic plants universally, what are the odds that all the 300-400 plant species use the same or a similar secondary chemical and that it's all the same intensity over 1000's of aquarium owners?

Trillions to one.

You still like them odds?

In natural systems, which can be 10 liters to 10^100 liters and some are unidirectional like streams and rivers, where many plants come from, what good would it be in those cases? It'd be wasted and swept away.


The theory needs to explain the observations.
This one does not even come close.

Germination does.

That is the key to weed science, you can control the germination of the crop and the weeds, you have control over the system.

I find it amusing that there's so much talk and haggling over algae and plants outcompeting algae for nutrients, yet few folks...............
ever consider plant= plant competition for CO2, NO3, or plant-plant interactions(I've never found an inhibiting effect here either to date).

Competition for CO2 when you have differences between plant abilities to take it up and the limited ability of us to measure CO2 and the differences within the aquarium of CO2 ppm, seems like a more important area to focus on if this is some area of pursuit.

But algae are not that hard to figure out, look at what gerimates them to bloom. You know that and are able to do it, then you have a good idea of at least one way to induce that species etc, they might be other ways to induce the growth however.

Regards, 
Tom Barr


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## spinycheek (Apr 26, 2008)

I'll agree with the low tech tank idea. My low tech tank with only indirect light, a decent bioload, no CO2, no ferts, only silica sand substrate has hardly any algae, yet the plants thrive. I've even had dead fish in there with no algae outbreaks and I drip ammonia in to ready the biofilter for new fish, still never algae. 

So I think there is something going on that nobody's figured out yet. I'm sure algae control is a multi-part problem, but it is certainly more than ammonia, CO2 and light.


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## EdTheEdge (Jan 25, 2007)

Wow... what a GREAT thread!

Thanks everyone!


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## Robert H (Apr 3, 2003)

To me this is a conversation quibbling over symantics and scientific theroy, not practicality. If you have a tank full of nothing but Anubias or some other slow growing plant, with intensive light and high levels of C02, and 10ppm N03 then you are going to have a tank full of algae. Under the same exact condtions but with a tank full of Bacopa monnieri you will have significantly less algae (at least for a period of time) and I challenge anyone to prove anything different!

Balance, and moderation will achieve more favorable results in limiting algae long term with either low tech or high tech than any other factor. Thats why when you look at aquariums from authentic dutch aquascapers they are algae free, and the same for devote followers of Diana Walstad, or Amano. Finding a balance that matches the growth rate of your plant load is what works. Thats what out competes algae



> You need to offer support for this, it's never bene shown ever in any live system(eg not extracts of plants in little test wells etc) to date............


I thought your friend Ole proved that hornwort inhibited algae. He wrote an article about it thats all over Tropicas WEB site, I seem to remember.


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## JDowns (Mar 6, 2008)

Robert H said:


> I thought your friend Ole proved that hornwort inhibited algae. He wrote an article about it thats all over Tropicas WEB site, I seem to remember.


From reading that article I draw the conclusion that Ole is at least very skeptical at the idea. Or maybe I'm missing Ole's true feelings on the matter.



[email protected] said:


> Personally, I do not see much ecological relevance in these kinds of experiments. At best, they may be used to look for potential candidates of true allelopathic behavior because the studies, after all, demonstrate that the plants contain toxic compounds. However, many of these studies take the conclusion much too far and recommend using the plants for aquatic weed management or algae control without the necessary documentation for allelopathic behavior in nature.


and



[email protected] said:


> _Hopefully, this article has provided you with sufficient knowledge so that you are naturally skeptical next time you meet these allegations on miraculous algae control by means of allelopathy. The best algae control will always be a densely planted aquarium with a limited stock of fish combined with frequent water exchange. In particular the last point probably prevents allelopathy to become important in planted aquaria since the toxic chemicals never build up to significant concentration levels and therefore the effect, if any, will never materialize._


Source of article

http://www.tropica.dk/article.asp?type=aquaristic&id=531


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## Homer_Simpson (May 10, 2007)

JDowns said:


> From reading that article I draw the conclusion that Ole is at least very skeptical at the idea. Or maybe I'm missing Ole's true feelings on the matter.
> 
> 
> 
> ...


Very interesting thanks for posting that. 

I have always been a strong proponent of minimal stocking levels and densely planting tanks, along with low light as I have always found that I achieved the best results doing this.

I know many people have had success with Diana Walstad's Natural Planted tank method, so I mean no disrespect when I post this it is what I experienced. When I set up my 5 gallon hex as a natural planted tank, it was the worst plant growth that I had ever seen, algae took root in a hurry, and worst of all nothing would stay alive in that tank, even normally hardy fish like Endler's Live Bearers and Betta got ill and died. Water parameters were normal, so it defies logic. The problems all started when I decided not to do water changes.

When I converted this tank to a Tom Barr type low tech, unbelievable plant growth, no fish deaths(lol, an otocat one of the most sensitive fish around is still alive 8 months later), no algae(other than some hardly noticeable green spot). I do weekly water changes and add ferts weekly.

You can read more about my experiment at: http://azdhan.googlepages.com/thelostworld2

In order to be convinced of anything, I need to see it and experience it, not hear rhetoric, speculation, and assumptions about what is or is not, or what is the right way or wrong way of doing things. Based on my experience and observations, Tom Barr is on the ball and I have no factual basis to doubt him or be skeptical of what he says.

I also haven't given up on topsoil totally. The same topsoil that I used in the 5 gallon hex natural planted that I had no luck with is the same one that is undergoing mineralization. I am going to see if the mineralized topsoil yields any different results - stay tuned for the sequel.


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## theredben (Dec 28, 2008)

*Re: The NH4/NO3 issue*

Assuming that we can safely call terrestrial plants and aquatic plants pretty closely related, there is something else to consider when talking about preference between NH4 and NO3. It has been shown that EVERY plant has a different preference, that's right, each plant has a different ratio of NH4:NO3 that it will grow best in. So trying to talk about certain ppm ranges is pointless. 

A general assumption based on terrestrial plants not backed by scientific data would say that the NH4:NO3 ratio preferred by some plants would kill any fish in the tank.


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## crabcake (Dec 19, 2007)

i have not read through this entire thread and i see that others have raised related points but i would like to underscore the notion of the different ecological roles of algae and higher plants. whatever scientificaly understood or mysterious actual mechanisms that they might be expoiting it is important to consider simple algae as organisms that prosper during the early stages of ecological succession, and higher plants as organisms that do better in later stages of succession with more "stable" conditions. 

in nature, algae bloom after disturbances, such as floods or severe droughts, that compromise the growth of true plants. they also do well where conditions are artificially skewed toward early succession, such as in a lake where nutrient pollution is dumped--even though plants may be present, they are unable to utilize all of the extra nutirents--or a newly established aquarium.

so, for the practical problem of favoring plants in an aquarium it should be advantageous to emulate the conditions in undisturbed natural ecosystems. light is one of the important variables in this relationship, so a low-light tank with little algae growth could be considered to be a good simulation of a healthy area in the wild where the higher plants have grown up and outcompeted algae for available light. biodiversity is another important factor. during greenwater blooms there is a predictable response to the passage of time as microscopic creatures that prey upon the bloom-causing _Euglena_ sp. protists build there numbers and eventually consume most of them.


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## plantbrain (Dec 15, 2003)

spinycheek said:


> I'll agree with the low tech tank idea. My low tech tank with only indirect light, a decent bioload, no CO2, no ferts, only silica sand substrate has hardly any algae, yet the plants thrive. I've even had dead fish in there with no algae outbreaks and I drip ammonia in to ready the biofilter for new fish, still never algae.
> 
> So I think there is something going on that nobody's figured out yet. I'm sure algae control is a multi-part problem, but it is certainly more than ammonia, CO2 and light.


You do not have enough light to drive germination using NH4, try adding a lot more light. You are light limiting for most species of algae, but not the plants.

So that's to be expected.
This is why the non CO2 planted tanks are so tough and easy over time.
You are not comparing the planted tank on equal terms, so the causal factors will also change:thumbsup:

Add more light and see if you can actively induce algae.
If you want to learn about causual factors of algae, learn how to germinate and grow algae.

Pretty simple concept, but folks here only want to speculate and not do any test to see. They want to get rid of algae, not induce it. So they never test and see if they can actively induce algae.

Regards, 
Tom Barr


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## plantbrain (Dec 15, 2003)

Robert H said:


> To me this is a conversation quibbling over symantics and scientific theroy, not practicality. If you have a tank full of nothing but Anubias or some other slow growing plant, with intensive light and high levels of C02, and 10ppm N03 then you are going to have a tank full of algae.


You mean like Luis's or mine here?:










No algae and quite a few folks have seen my tank.
NO3 is 25-30ppm, PO4 is about 2ppm or so.
2x65W and 150W HQI.

Go figure.



> Under the same exact condtions but with a tank full of Bacopa monnieri you will have significantly less algae (at least for a period of time) and I challenge anyone to prove anything different!


Easy, I just assume that the CO2 is much higher than it actually is, say I assume it's 30ppm and not 8ppm. Then I'll get algae. 

In general, the faster RATES of growth need supplied with a faster rate of inputs, CO2, nutrients etc, and light can help drive that, but it's not absolute.
Cases can be made where you have such conditions.



> Balance, and moderation will achieve more favorable results in limiting algae long term with either low tech or high tech than any other factor.


Balance?
Nice general term, but meaningless really, you need to be specific.
Moderation is good, but most go for high light. They will not listen to that from either of us.



> Thats why when you look at aquariums from authentic dutch aquascapers they are algae free,


Any non authentic Dutch out there?:icon_roll
Sorry, you are wrong here, they have algae like non CO2 and ADA folks.
There's no algae free method that works for everyone.



> Finding a balance that matches the growth rate of your plant load is what works. Thats what out competes algae


Now you are talking about rates, but it's still not competition because it's not for the same resources at these scales. A spore can be exposed to non limiting conditions(and typically is) for nutrients and CO2, light etc, but be stuck deep in the sediment. When a person uprooting, or a flood pulls it up, then it has access to the light, then can grow into an adult alga.

A plant is already there and has access to the light, it's got far more nutrient demand and CO2 demand than any algae. Many algae spores need a critical amount of light to germinate, most plants need very little comparatively.



> I thought your friend Ole proved that hornwort inhibited algae. He wrote an article about it thats all over Tropicas WEB site, I seem to remember.


Having spent several days with Ole recently in person, I do not think he's fond of the notion of allelopathy causing any issues for algae. We did agree that it's not the Science that causes issues, rather the hobbyists wanting to believe everything they think.

Ole is not the only one, every researcher at UF, UCD, you name it, will tell you the same thing.

"Inihibit" is also a rather vauge term, you need % inhibition. 10% is not much in log phase growth of algae(how algae is tested against, not well established or old 1/2 dead algae), and most aquarists would/could not tell a difference.
We are only talking about slowing down a specific species of algae here also, not killing or eliminating it and only during the log phase of it's growth.
Such test and are looking to answer a very specific question under a certain set of conditions. How you then apply the conclusions is where many get lost.

Diana made clear that it was speculation as a causual factor, she said she was speculating and guessing.......it was a valid speculation, but folks never read that part. They assume it must be right and fact.

There's the issue often times, folks cain't read.
They hear only what they want and not the rest of the story.

Regards, 
Tom Barr


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## plantbrain (Dec 15, 2003)

theredben said:


> Assuming that we can safely call terrestrial plants and aquatic plants pretty closely related, there is something else to consider when talking about preference between NH4 and NO3. It has been shown that EVERY plant has a different preference, that's right, each plant has a different ratio of NH4:NO3 that it will grow best in. So trying to talk about certain ppm ranges is pointless.
> 
> A general assumption based on terrestrial plants not backed by scientific data would say that the NH4:NO3 ratio preferred by some plants would kill any fish in the tank.


But we can place NH4 into clays in the sediment where they do not expose the fish:thumbsup: but are still avilable to the plants' roots. We also have fish...........which slowly release low levels of NH4 waste to the plants and bacteria, so while not a high residual NH4 is present, the overall % is still similar due to continuous input from fish.

Regards, 
Tom Barr


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## plantbrain (Dec 15, 2003)

crabcake said:


> i have not read through this entire thread and i see that others have raised related points but i would like to underscore the notion of the different ecological roles of algae and higher plants. whatever scientificaly understood or mysterious actual mechanisms that they might be expoiting it is important to consider simple algae as organisms that prosper during the early stages of ecological succession, and higher plants as organisms that do better in later stages of succession with more "stable" conditions.
> 
> in nature, algae bloom after disturbances, such as floods or severe droughts, that compromise the growth of true plants. they also do well where conditions are artificially skewed toward early succession, such as in a lake where nutrient pollution is dumped--even though plants may be present, they are unable to utilize all of the extra nutirents--or a newly established aquarium.
> 
> so, for the practical problem of favoring plants in an aquarium it should be advantageous to emulate the conditions in undisturbed natural ecosystems. light is one of the important variables in this relationship, so a low-light tank with little algae growth could be considered to be a good simulation of a healthy area in the wild where the higher plants have grown up and outcompeted algae for available light. biodiversity is another important factor. during greenwater blooms there is a predictable response to the passage of time as microscopic creatures that prey upon the bloom-causing _Euglena_ sp. protists build there numbers and eventually consume most of them.



You have the best overview. Ecology is a key part of the understanding of the differences. Not everyone is good at ecology however. I'm not particularly good at sport statistics either, but some are. I do not argue with them either nor bother trying, it does not interest me, but I still like to play sports. Everyone has their strength and weaknesses. If you ask 5 folks what happened at an accident, you will get different stories, not everyone will see the same things.

We still should address the observations, test etc, discuss them to make sure folks are all on the same page, then come to a conclusion that makes some sense. The Conclusion needs to pass the muster of being logically reasonable.

In nutrient dumping waste water systems, if you add more nutrients to a lake with 30-50% weeds, you get more weeds. If you dump the saem load into a lake without weeds, you get algae. As you mention, if you distrub the weeds, remove them seasonally etc, then you have some blooms at some part of the year, weeds other parts, etc and different algae successions.

In our tanks, where we have control over everything, we can make the system very stable, low/moderate light, good CO2(or non CO2- some trade offs here)/ample nutrients for the plants(sediments and water column sources). The distrubance is "us".

We can selectively chose what to remove, add etc.
I do not think there is that much diversity issue here, but the bacteria play some roles as does good root establishment. But........It's our own fault when we get algae:redface:

Not the nutrients as many like to say.
Nor is there really competition between two similar organisms, because.........they are not similar(scale, rates of growth, nutrient needs, uptake kinetic differences, surface to volume ratios, structurally, light demands, life histories, life spans etc).

These are not new things or concepts.
But many just do not get it.

So they fall back on other things like the "algae are outcompeted", they do not care why that much really. This is a social issue, not a science issue.

I have the same issue with sport talk, I do not care, I'd rather kick a soccer ball, not watch a game and talk and argue about it.

Same for planted tanks, and with that, off I go

Regards, 
Tom Barr


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## flanders (May 3, 2008)

plantbrain said:


> Pretty simple concept, but folks here only want to speculate and not do any test to see. They want to get rid of algae, not induce it. So they never test and see if they can actively induce algae.
> 
> Regards,
> Tom Barr



Yes! When I first got into planted tanks, my wife thought I was crazy when I would try to grow algae. I thought it would be cool to provide food for some of my algae eating inhabitants. There were of course times I had absolutely no algae for weeks, and times where I thought I might lose all my plants. Now, I hardly have any problems with algae and actively try to grow algae when certain fish are breeding (I think fry eat some of the microorganisms around algae). I digress....


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## crabcake (Dec 19, 2007)

this is an interesting discussion.

you know i have thought that it would be cool to find a way to make an aesthetically appealing and scientifically interpretive display with just algae. 

this would be a challenge. the real tricky part would be maintaining the algae over the long term.


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## unirdna (Jan 22, 2004)

Robert H said:


> If you have a tank full of nothing but Anubias or some other slow growing plant, with intensive light and high levels of C02, and 10ppm N03 then you are going to have a tank full of algae... and I challenge anyone to prove anything different!


I enjoyed reading this discussion. roud:

Robert, if you consider 150w halide light over a 48g aquarium to be high light, then I have achieved your scenario. Click on the "ADA 90cm" link in my signature to see a photo.


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## Homer_Simpson (May 10, 2007)

plantbrain said:


> .... They want to get rid of algae, not induce it. So they never test and see if they can actively induce algae.
> 
> Regards,
> Tom Barr


So true.... but you know that once you get this stuff it can be a real PITA to get rid of. With my 40 gallon tank, I spent 3 months pulling out my hair, dosing Excel, increased water changes, increasing plant density, manual removal, monkeying around with light, amassing a team of algae eaters, before the algae decided to peacefully leave. Luckily the strategy of containment and prevention worked. It was an exercise in frustration, so while it may be fun to induce algae from a scientific point of view to isolate what causes it is no fun going to war with and battling it. The battle tends to get drawn out, takes away from enjoyment of the tank. I want to enjoy some quality time with my tank in an otherwise hectic world where time is a premium. I have neither the time or patience to constantly battle algae. I will do what I can to prevent it and not induce it....Thank you.

P.S. I can live with and don't mind a little bit of algae as long as it does not overtake by tank and get unruly. I have learned to make peace with algae as I have learned that a 100% algae free tank may be a futile goal. Resistance is Futile!


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## mistergreen (Dec 9, 2006)

plantbrain said:


> Aquatic plants when growing well and not limited etc, modify the system, the plants define it, not the nutrients.



so how do plants modify the system so that algae doesn't have the chance to germinate?


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## Hoppy (Dec 24, 2005)

mistergreen said:


> so how do plants modify the system so that algae doesn't have the chance to germinate?


I don't know for sure what Tom was referring to, but plants modify the system at least two ways: first they shade portions of the tank, especially down at the substrate. Second, they consume the minute amounts of ammonia continually being supplied by the fish, so the concentration cannot build up to where algae spores can sense/use it.


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## plantbrain (Dec 15, 2003)

mistergreen said:


> so how do plants modify the system so that algae doesn't have the chance to germinate?


Essentially they stablize it and control it, the plants thus control the system, not the nutrients.

They control it as Hoppy mentions, as well as reducing flows, increase sedimentation, basically buring the spores.

No light, plenty of CO2, NH4 etc, PO4, NO3, Fe etc etc etc, all the nutrients and CO2 in the world.....but if you do not have enough light to start things off, and get those spores to the light zone, then none of that matters.

Plants go nuts and grow up to the surface, shade out virtually everything below, our tanks can and do get that way from time to time.

Then we hack them hack, uproot, move plants around etc, pulling up plenty of spores, but if you do a lot of water changes, this is mitigated.

Ask yourself this question: if you where an alga spore, what signal/s would you look for to germinate and grow?

Temp?
Light(pretty obvious)
CO2 changes?
O2 changes?
NH4? 

What other things occur in sediments with lots and lots of roots?
The roots add lots of O2, and that produces a large intense colony of bacteria able to remove NH4 very well. It(the bacterial colony) also cycles waste very rapidly, much better than many think.

This means there's little waste in the system laying around at any one time.

So say you suddenly stop adding CO2 for awhile, say 2 weeks, what happens to plant growth? Stops pretty much............and if growth stops or slows way down...what happens to O2 production and root release of O2?

Drops..........way way down also.

These things are linked and often form "cascades", that can generally lead to algae, the plants are doing poorly, then the effect is generally some other critter or algae etc will take advantage.

But when the plants do well, and they have a stable environment, then there's very little chance of that. Some of the planted springs in Brazil, Texas, and many in Flodia have been stable for 500 or more years at least.

Some of them come right out of a nutrient rich PO4 mine or relatively rich underground water source rich in CO2.

If the ag run off is added to this ground water and spetic tanks leakage, this adds more CO2 and more N, this changes things on a much larger scale. Then these systems get degraded in patches, sadly this is occuring in many springs in FL.

Even these stable natural systems are not as stable as ours. They vary quite a bit in terms of light and there's a strong correlation between light and algal biomass production in every spring on plant leaves, artifical and natural media.

We have the same light which we can vary in time/duration and intensity, sun light is not the same.


Homersimpson also eludes to a basictenant in Restoration Ecology and Weed Science: once you have perturbed the system and have a pest, you have to out a lot more effort to restore the system back to the way is was, in Chemistry, they call it the energy of activation to get a chemical process started to go a certain way/direction.

So you would have had to much less work to watch the tank and add a bit more CO2 tweaking etc, maybe a water change or two more than you did, clean better, clean the diffuser more often, prune more routinely, not uproot, but "top" more etc.

The old adage" an Ounce of prevention is worth and pound of cure".
This applies to Weed Science and invasive species in general, be rapid and aggressive to respond to the system if it's going a way you do not like.

Don't wait, postulate, discuss and stare at it and balme everything under the sun, kick it's butt asap. This is not some scientific thing, it's common sense.
Nail it.

Horticulture can be complex etc, but the "how" tends to be surprisingly simple. You just have to keep an eye on things and and stay on top of it.
Do what helps the plants to grow, the algae and other pest are less troublesome and you rarely bother with them or have issues if you focus on the plants.

I got pissed off at the bad advice in the past and started thinking, "well, since I have bad algae, might as well see if I can induce it" and then once I learned that, " I know how to correct the issue and can repeat it, so I have no more worries about this specific species of algae, so I can test it as much as I want".

So I learned a lot about the pest in question.

Few aquarists I've ever met have ever bothered to do this, I can count them on one finger.:redface: The logic is easy to understand, but folks don't wanna. 



Regards, 
Tom Barr


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## prjct92eh2 (Apr 8, 2008)

From what crabcake and Tom have posted, i think i am finally understanding the relationship between algae, the aquarium and nature. If i understand correctly, nature is generally stable (minus a flood, hurricane, etc.) and therefore relatively algae freee. By using Tom's EI from the setup of an aquarium, we provide consistent and relatively stable amounts of nutrients, which along with stable lights and CO2, the same way nature does and therefore limit algae by never giving it an unstable system to take hold in.

I experienced this when i first delved into the planted tank with my 38 gallon tank. I had hair algae that drove me crazy when i first set it up. I kept reading all the different reasons into what could cause it and although i kept my CO2 and light the same, i kept varying the amount of Fe, NO3, and PO4 each week. I did this for several months and finally said screw it and went back to following the EI regimine to the T. Low and behold, after a month of the same, _consistent_ dosing i noticed a drastic reduction in hair algae.

Great thread guys!


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## plantbrain (Dec 15, 2003)

prjct92eh2 said:


> From what crabcake and Tom have posted, i think i am finally understanding the relationship between algae, the aquarium and nature. If i understand correctly, nature is generally stable (minus a flood, hurricane, etc.) and therefore relatively algae freee. By using Tom's EI from the setup of an aquarium, we provide consistent and relatively stable amounts of nutrients, which along with stable lights and CO2, the same way nature does and therefore limit algae by never giving it an unstable system to take hold in.
> 
> I experienced this when i first delved into the planted tank with my 38 gallon tank. I had hair algae that drove me crazy when i first set it up. I kept reading all the different reasons into what could cause it and although i kept my CO2 and light the same, i kept varying the amount of Fe, NO3, and PO4 each week. I did this for several months and finally said screw it and went back to following the EI regimine to the T. Low and behold, after a month of the same, _consistent_ dosing i noticed a drastic reduction in hair algae.
> 
> Great thread guys!


Be careful when comparing and assuming nature and our very controlled aquarium s are similar.

The natural systems tend to be much more varied actually.
Light, a lot lot more of of it, seasonally, temps, etc, nutrients, water levels etc, only a very few places have stable conditions year after year.

You are correct in the general part though, you never allow a disturbance to allow the algae to start and take a foothold. The disturbance can be a limiting factor to growth, say CO2 is the most common one(same in natural systems also).

You could have had algae for a few reasons. Nothing to do with EI, a simple change in the CO2 or light could have far more dramatic changes than the nutrients. We assume the CO2 is the same if we do nothing to adjust it, but this is not true and bad assumption.

If we do not verify it, and confirm it is the same as far as what the plants are exposed to.............then we cannot really say. We can add more and see also,which is what most folks end up doing.

In order to get results with CO2, you need to have good nutrients so they do not play a limitation role, then moderate to low light(higher light will increase the demand for CO2 and nutrients, moderate to low light will make this range easier to target) so that the demand for CO2/nutrients is also not that strong.

This way you get good non limiting nutrients and CO2.

With lower/moderate light, while this does reduce the rates of plant growth(not awlays a bad thing if they are growing well and algae free), importantly, this also grows algae slower as well if present.

So algae eaters can be more effective as can pruning and general care.

So if anything, such a tank is a light limited tank more than anything.
That is *the least wasteful* approach. You can use less nutrients, less CO2 and less energy, less inital cost and resources than any other possible method.

While glaringly obvious logic and common sense, many get lost in the nutrients, not seeing the larger picture that's more important: light and CO2.

Then we get folks haggling over which method is "best", each one claiming that their's is:icon_roll Some really do not give a hoot about a few ppm of extra NO3, some very much do. Either way, you cannot address either goal without addressing CO2 and light and use those two to help better make either goal easier.

But some wanna limit PO4 and then add insane amounts of light, never really measure their CO2, not keep any fish etc. Then think everyone else must have this same goal too.

Very few do.

You do get some algae growth reduction with some nutrients limited intially, but the plant growth is slower also, some see that and think this must be the key and that theory of PO4 limitation must be right still! We do see some reduction, but rarely elimination of all visiable signs, and we also know that limiting PO4 strongly reduces CO2 demand also, so they need less CO2 now than before. Adding non limiting nutrients will maxmize the CO2 uptake demand, for rather obvious reasons, limiting something else will reduce CO2 demand. So while they limit PO4, they also affect CO2 and virtually ignore that part/impact. Everything must be a direct cause according to them. No, one thing will affect and influnce others in plant nutrients and growth. This is essential stuff. If it is, as they claim, a direct relationship, then where is my algae? I've asked this question for well over a decade. No one has ever answered it nor can really.

However, none of these bozos can explain why other tanks with lots of PO4 and high rates of plant growth do not have algae. They start changing their claims and saying that some secret tap water component, or allelopathy, or any number of hocus pocus tricks. But we see this over a wide wide range of aquariums, over long time frames over thousnads of aquariums.

And that's the failure in the logic. Their theory has been falsified. And many take it personally and make it their life's mission to show otherwise. Knock yer self out:redface:

So why do folks have issues still?
Plenty of folks believe many things and make assumptions about CO2, light and nutrients. The theory itself is not to blame, we are. We screw everything up, some of us are really good at it:redface:

This is a social human issue. 
We assume that the light is high and must be better because of that, we assume that the CO2 is great, when in fact it might be limiting, we assume our filter is clean, that the current is good, that the CO2 ppms are the same throughout the aquarium, that our test kits are right etc.

None of this has to do with any method really or nutrients.
But makes a huge difference. So we expect to see many folks with issues no matter what the method, and atlas, we do.

We also see successes with most methods, as we might expect, so is it the method or the people? The people mostly, and their matching of their goals and the method they chose.

We need to look at the successes and understand those, then try and mess with them to see what really matters. Do we get algae if we add more NO3? PO4? Light? What are the best ways to test that so we do not confound things by poor CO2 or low NO3 etc etc??

It's not as simple as many might first think.
But after testing and seeing, we have a good understanding about what aspects make a method easier, and how to fix and rectify the aquarium to have better plant health. 

Regards, 
Tom Barr


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