# Why is increase macro-nutrients supposed to help defeat algae?



## learn2turn (Sep 16, 2008)

I don't get why increasing macro-nutrients helps defeat algae. Macro is NPK right? Maybe this is because I did a reef tank a long time ago but I thought the whole idea was to limit these to as near zero as possible so only the good stuff would grow.

I would think that adding these would cause an algae bloom, not stop it.


----------



## ashappard (Jun 3, 2006)

in the planted tank the idea is to limit algae by promoting plant growth.
we add macros to make the plants grow well, and with proper amounts of nutrients plants get the upper hand on algae. 

algae still survives, its there just waiting for me to screw up. :wink:
but I cant see it, and most of the time algae doesn't bloom as long as the plants are healthy.
then theres green dust algae..


----------



## learn2turn (Sep 16, 2008)

ashappard said:


> in the planted tank the idea is to limit algae by promoting plant growth.
> we add macros to make the plants grow well, and with proper amounts of nutrients plants get the upper hand on algae.
> 
> algae still survives, its there just waiting for me to screw up. :wink:
> ...


Still doesn't make sense to me. If I had 57 picnic lunches (nutrients) and I dumped them all over the ground. Lots of happy people (the plants) could pick them up and eat like crazy but the ants (algae) could get as much as it wanted.


----------



## davemonkey (Mar 29, 2008)

learn2turn said:


> Still doesn't make sense to me. If I had 57 picnic lunches (nutrients) and I dumped them all over the ground. Lots of happy people (the plants) could pick them up and eat like crazy but the ants (algae) could get as much as it wanted.


But in the case of plants vs algae, the plants are more efficient at getting the nutrients, so the algae does not get fed. You just have to make sure the "lunches" are well-rounded meals. For instance, if you go too lean on Phos, then the plants will leave 'crumbs' behind and the algae will gobble them up.

-Dave


----------



## ashappard (Jun 3, 2006)

learn2turn said:


> Still doesn't make sense to me. If I had 57 picnic lunches (nutrients) and I dumped them all over the ground. Lots of happy people (the plants) could pick them up and eat like crazy but the ants (algae) could get as much as it wanted.


a suggestion would be to try it. read up on what dosing regime is recommended by biomass and lighting. Add adequate CO2, and flow to a planted tank. You'll see that it is a valid strategy and can also be extremely stable if the maintenance routine is consistent.

you do not need chemical filtration, you do not need to regularly limit nutrients by extracting them from the water column. Believe me, this hobby has already gone through many cycles of 'limit nutrient _x_' over the years and the results are not as pleasant as just letting the plants have what they need, keeping the tank clean and watching the results. The idea still pops up occasionally, especially in the limiting of phosphate to fight/prevent algae.

freshwater systems have different needs, and reefkeeping methods while completely valid in a reef do not necessarily transfer into planted aquaria. The things that we limit in a reef are things that are needed in a healthy planted tank.


----------



## bartoli (May 8, 2006)

learn2turn said:


> I don't get why increasing macro-nutrients helps defeat algae. Macro is NPK right? Maybe this is because I did a reef tank a long time ago but I thought the whole idea was to limit these to as near zero as possible so only the good stuff would grow.
> 
> I would think that adding these would cause an algae bloom, not stop it.


It seems to me the assumption was that due to the lack of macro-nutrients, plant cannot use other nutrients in the water. Those left over nutrients then cause algae bloom. By adding macro-nutrients, plants can take up the left over nutrients. Thus, stop or prevent algae bloom.

But I would think that if there is no left over nutrients, the added macro-nutrients will themselves become left over which will then cause algae bloom.


----------



## ashappard (Jun 3, 2006)

bartoli said:


> It seems to me the assumption was that due to the lack of macro-nutrients, plant cannot use other nutrients in the water. Those left over nutrients then cause algae bloom. By adding macro-nutrients, plants can take up the left over nutrients. Thus, stop or prevent algae bloom.
> 
> But I would think that if there is no left over nutrients, the added macro-nutrients will themselves become left over which will then cause algae bloom.


Its possible that over-thinking the process causes algae bloom. 
so I don't do it. no algae bloom! 

seriously, abundance within reason aids stability. If nutrients exist in great enough quantities in proper ratios to each other the plants will thrive. These ranges are wide enough to give us plenty of room to play with things like color, leaf shape etc. and still not have an algae issue.


----------



## bartoli (May 8, 2006)

It is safe to say that abundance within reason aids stability. But how does one know whether the amount of macro-nutrients in a tank is abundant within reason? If one keeps dosing macro-nutrients whenever there is an algae bloom, there can be too much macro-nutrients ended up in a tank and therefore making things worse.


----------



## ashappard (Jun 3, 2006)

bartoli said:


> It is safe to say that abundance within reason aids stability. But how does one know whether the amount of macro-nutrients in a tank is abundant within reason? If one keeps dosing macro-nutrients whenever there is an algae bloom, there can be too much macro-nutrients ended up in a tank and therefore making things worse.


thats true, but I wouldn't stick to a dosing schedule knowing I'm feeding a bloom. I'd change water / clean up and regain stability / return to dosing. probably also try to figure out where something went wrong. maybe it was dosing, maybe something else. flow / CO2 and lighting are also important.

for some ideas about 'abundant within reason' check out the write ups on PPS / EI dosing methods. There are also several posts here and elsewhere about ratios of macro nutrients in a planted tank. I manage my dosing by the ratio of KNO3 to KH2PO4, at around 5:1. Depending on the tanks grow rate and what I want to accomplish, I'll add up to 10-15ppm per day of NO3.

of course if I notice something drifting out of whack, I'll re-visit my dosing and adjust. After a while it gets easier to stabilize a tank at a desired growth rate. Or you can tweak dosing to get the plants to have a certain appearance. fun stuff, really.


----------



## overboard (Mar 11, 2008)

I was using Flourish and Kent Freshplant and Seachem's liquid macros, and I had algae and wasn't getting the results that I expected. I would change something and get an algae bloom, and it would make me afraid to fertilize. Then I got some dry fertilizers and a scale and took a deep breath and went for it. The results were astounding. Algae was reduced or eliminated, and some plants that looked fine but just didn't seem to get bigger, got way way bigger. Out of control bigger in some cases- a cool problem to have. Anyone want some water wisteria?


----------



## hoppycalif (Apr 7, 2005)

Algae grow when there is a great chance that they can complete a growth cycle and reproduce. All other forms of life also expend most of their energy trying to reproduce. Aquariums have been around for perhaps 100 years, but natural water bodies have existed for something greater than 1,000,000 years. It should be obvious that algae evolved to be able to reproduce in natural settings, not in aquariums.

It appears that in natural settings algae and plants compete almost exclusively for light. Naturally growing aquatic plants tend to grow to the surface and cover it to get as much light as possible, while algae have to stay where they are, under the water surface. (Yes, this is a generalization.) In order for algae to have the best chance to complete a life cycle and reproduce they have to start growing when there are few aquatic plants growing, when aquatic plants won't be covering the water surface until after the algae have completed their reproduction. So, algae evolved to sense things that indicate that they will be successful in reproducing.

Two of those things seem to be the sudden presence of ammonia (dying plants and other water life?), and a drop in dissolved CO2 in the water (?). Once those things tell algae to start growing they will grow tenaciously until they finish what they are trying to do - reproduce. It takes very little nutrients for algae to grow, compared to plants. The consumption of nutrients is roughly proportional to the mass of plant or algae tissue. Algae, even when abundant, has very little mass, but plants have orders of magnitude more mass. So, algae don't need nearly as much of any nutrient as plants do.

Algae does not compete with plants for nutrients, because they don't need to. There are always more than enough nutrients for algae in our tanks. (Keep in mind that we are not discussing natural bodies of water now.) These things mean we should try to avoid any of the "signals" that tell algae to start growing. We know that ammonia will trigger algae to start, and we know that allowing the concentration of CO2 in the water to drop will also trigger algae to start growing. We also know that plants consume ammonia very quickly when it does appear. So, if we have a lot of fast growing plants growing, ammonia never exists in the tank except in very tiny amounts for very brief moments. That is why having a lot of fast growing plants, which means having adequate nutrients for those plants, is a protection against algae.

Is all of the above really true? Who knows? It is certainly an explanation that fits the known observations by a lot of people. So, it has a good probability of being true.

Natural bodies of water are another story entirely. Not all of those bodies of water have any aquatic plants in them. So, what triggers massive algae blooms there would likely be different. Other natural bodies of water have very little CO2 dissolved in the water - again algae blooms would be different. But, some natural bodies of water have both high CO2 content and lots of healthy plant growth - those should behave similarly to our aquariums.

There are at least thousands of different algae on earth. We face only a tiny percentage of those in our aquariums. What happens in nature may well involve algae types we never see in our tanks.


----------



## Edward (May 25, 2004)

*How to combat algae?*
Algae can not be starved to death, it goes dormant and waits. So how is it done? 
Until today there is not much evidence to support any theory because few laboratories are interested to work on such insignificant market. However, most likely healthy plants produce chemical warfare and favorable conditions for beneficial micro organism which suppress and control algae development. So, if we think of it, it does make sense unless we go with some paranormal explanation. Now, the same applies to algae, if algae is thriving, plants are doing poorly despite any pro plants conditions. So yes, we need to feed the plants in order to get rid of algae or vice versa. Because we prefer plants over algae we need to feed the plants with elements plants are made of

C
Ca
Mg
N
P
K
S
Mn
Fe
Zn
Cu
Bo
Mo

That's all the elements plants need to grow healthy and keep algae under control.

Thank you
Edward


----------



## chagovatoloco (Nov 17, 2007)

Healthy plants release chemicals that inhibit algae. There are many different chemicals plants release to defend them selves. So if we go back to the food in the part the people eating are fighting off and stopping ants from coming. Just like we all do when we eat in the park stopping bugs and ants from getting our food before we do. The ei index shows this is true, ferts have a target level so as long as there is enough we must go to other things such as photo period and light intensity.


----------



## hoppycalif (Apr 7, 2005)

I lack the chemical knowledge to dispute that "Healthy plants release chemicals that inhibit algae." But, I am almost certain it would be possible to test that theory. One way would be to take a large tank, say 125 gallon, plant it heavily with a big variety of plants, let it grow healthy and algae free. Then, take a 20 gallon tank that is having algae problems and replace the water with water from the big tank. If the theory is correct you can do this repeatedly and every time it will at least greatly reduce the algae in the 20 gallon tank. If it doesn't, you could do daily water changes using water from the 125 gallon tank - 6 days in a row - and that would stop the algae cold, if the theory is correct. Of course, good science would require repeating this many times, and always getting those results.

I am surprised that people have not set up "farms" to generate this chemical filled water, bottled it, and sold it for its anti-algal properties. The only reason I can see why they haven't, if the theory is correct, is that the chemicals being generated are so fragile and short lived that it can't be done. But, I have to believe Seachem or Tropica would be able to get around that problem.

This is not intended to be snark or a put down of that theory. I am just curious about why the relatively easy testing hasn't been done.


----------



## chagovatoloco (Nov 17, 2007)

I got this from Diana Walstad's book, I believe the correct name is allelopathic chemicals. From what I under stand caffeine is one of these chemicals that we are more familiar with. I am not in to the el natural personally but I read the book for it's scientific input. Just trying to put more pieces of the puzzle together. If you google allelopathic chemicals you will find a lot of info on them.


----------



## hoppycalif (Apr 7, 2005)

chagovatoloco said:


> I got this from Diana Walstad's book, I believe the correct name is allelopathic chemicals. From what I under stand caffeine is one of these chemicals that we are more familiar with. I am not in to the el natural personally but I read the book for it's scientific input. Just trying to put more pieces of the puzzle together. If you google allelopathic chemicals you will find a lot of info on them.


Yes, you can find a lot about allelopathic chemicals, but it is always about terrestrial plants, and only a few of them. I have never found any article about such chemicals coming from aquatic plants. Even Tropica did some work on that, but ended up saying aquatic plants probably don't produce them. http://www.tropica.dk/article.asp?type=aquaristic&id=531 Still, the test I mentioned should demonstrate that they are present, if they are.


----------



## chagovatoloco (Nov 17, 2007)

Your right there needs to be some tests. I'm sure that this is not the first time you have heard of this, has there been any research to try to back this up. As I said I read about this in a book, I'm starting to think I should question what I read more. I have also read that this explains why some plants do not grow with others. Do you think there is any truth to that?


----------



## hoppycalif (Apr 7, 2005)

chagovatoloco said:


> Your right there needs to be some tests. I'm sure that this is not the first time you have heard of this, has there been any research to try to back this up. As I said I read about this in a book, I'm starting to think I should question what I read more. I have also read that this explains why some plants do not grow with others. Do you think there is any truth to that?


Both Tropica and Tom Barr have said that allelopathy is not a factor in aquariums. That makes me think it very likely isn't a factor in aquariums. Where I have a hard time accepting that it is is that for such a chemical to be effective in retarding growth of either some plants or algae it should be easily detectable and capable of being synthesized. In other words it couldn't be so subtle that detecting it would be terribly difficult. I think it is obvious that once an organic compound has been detected it is always a pretty short time before it is also synthesized. Who ever synthesizes such a chemical stands to make some good money from selling it, so I am pretty sure it would have been done by now. However, that doesn't mean it doesn't exist, it just suggests to me that it doesn't exist.


----------



## bartoli (May 8, 2006)

hoppycalif said:


> I lack the chemical knowledge to dispute that "Healthy plants release chemicals that inhibit algae." But, I am almost certain it would be possible to test that theory. One way would be to take a large tank, say 125 gallon, plant it heavily with a big variety of plants, let it grow healthy and algae free. Then, take a 20 gallon tank that is having algae problems and replace the water with water from the big tank. If the theory is correct you can do this repeatedly and every time it will at least greatly reduce the algae in the 20 gallon tank. If it doesn't, you could do daily water changes using water from the 125 gallon tank - 6 days in a row - and that would stop the algae cold, if the theory is correct. Of course, good science would require repeating this many times, and always getting those results.
> 
> I am surprised that people have not set up "farms" to generate this chemical filled water, bottled it, and sold it for its anti-algal properties. The only reason I can see why they haven't, if the theory is correct, is that the chemicals being generated are so fragile and short lived that it can't be done. But, I have to believe Seachem or Tropica would be able to get around that problem.


Plants adjust to their environment. A mere change in light intensity can cause the drastic action of discarding existing leaves and growing new ones. Therefore it is not that far-fetched for plants to release allelochemicals that are specific to the types and amount of algae found in the immediate environment. If that is indeed the case, moving the water to another tank (or extracting whatever compounds found in the water) may not work.


----------



## ashappard (Jun 3, 2006)

bartoli said:


> Plants adjust to their environment. A mere change in light intensity can cause the drastic action of discarding existing leaves and growing new ones. Therefore it is not that far-fetched for plants to release allelochemicals that are specific to the types and amount of algae found in the immediate environment. If that is indeed the case, moving the water to another tank (or extracting whatever compounds found in the water) may not work.


definitely a stretch. I don't think that anybody who has debunked allelopathy believes that the effect is a myth, but that in the aquatic systems we keep its effect is negligible to the point of being a non-issue. It will be the least effective tool at our disposal, and thinking that we can leverage allelopathy to keep a clean healthy aquarium is wishful thinking at best.

now, I'm not a botanist or a scientific person so flame away on this opinion, and I dont mind at all. I have been keeping planted tanks for many years (as many of us here have) and have developed a common sense attitude towards what happens in these aquariums. I know that aquatic systems are incredibly complex, and aquariums being miniature aquatic systems have their own complexities -- but there are many ways to simplify what goes on there without sweating the details or looking for an explanation that is more convoluted than need be.

Fertilization when done correctly gives me healthy plants. And _correctly_ usually just boils down to consistency in proper ratio. The ranges of acceptable nutrient levels are very wide, ratios are also forgiving up to a point. CO2, light, flow and clean water are the most beneficial tools I have for consistent health in tanks that can remain stable for many years. drop checkers / ph controllers / test kits / other stuff - not needed. I have not seen proof to this date that they are needed or even help more than a consistent maintenance and fertilization routine. drop checkers are one of the most misused and over-trusted pieces of equipment in this hobby.

One of the biggest mistakes I've made and continue to see others make is to overthink the processes in our aquariums and look for explanations or solutions that are less than obvious. I've learned that things like penac, tourmaline, and allelopathy (to name a few) are not to be taken seriously. Mainly because I have seen no true demonstration of their effectiveness in an aquarium that puts them above good maintenance / husbandry. Marketing hype does not count. keeping an 'open mind' is one thing -- false hope on unproven solutions is something else altogether.


----------



## chagovatoloco (Nov 17, 2007)

I haven't used a test kit in a while, don't use a ph controler and agree that ample fertilizer is a key. How ever a drop checker is a inexpensive way to get a good base line on co2. Allelopathy may not be as important as some of the books I have read have stated. As for over thinking, I'm just trying to get a better understanding of what is going on. Is that false hope?


----------



## bartoli (May 8, 2006)

ashappard said:


> definitely a stretch. I don't think that anybody who has debunked allelopathy believes that the effect is a myth, but that in the aquatic systems we keep its effect is negligible to the point of being a non-issue.


Did they give reasons for believing that the effect would be negligible?


----------



## ashappard (Jun 3, 2006)

bartoli said:


> Did they give reasons for believing that the effect would be negligible?


yes. Earlier in this thread, someone mentioned Tropica and they do have quite a bit of allelopathy information online. There is no effort to prove that the effect does not/cannot exist, they show many examples where aquatic plants are known to contain or produce toxins - they discuss a myrio that is known to secrete a substance that is an algaecide for example.

the confirmation that these toxins exist in certain plants is not enough to say having them in an aquarium will reduce/control/or inhibit algae. The studies do not demonstrate that  and the Tropica article notes :

_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._

the issue is that there is nobody demonstrating that in the typical aquarium the toxins / agents actually exist in quantities high enough to have any type of effect. Often, allelopathy is mentioned by an author and then there is the leap -- concluding that because allelopathy is real then it must be the reason for certain observations. Pedersen (the Tropica author in one piece I read) then takes issue with Diana Walstad directly, and for very good reason - read on :

_In her book "Ecology of the Planted Aquarium", Diana Walstad lists a number of observations of fish kills, plants dwindling away for no apparent reason and the like. She attributes all these "unexplainable" events to allelopathy in either higher plants or in algae. Personally, I find it unlikely that the following statement has anything to do with allelopathy: "For example, tanks with heavy plant growth often seem to have very little algae" (Walstad, 1999). It is much more likely that this general observation is due to efficient competition for resources (light, nitrogen, phosphorus and CO2) from the higher aquarium plants and this may prevent the algae from ever getting a hold in the tank. A natural question to pose would be: Can allelopathy be used to control algae growth in the aquarium? The answer would be NO! One would have to advocate lowering the water exchange, which would be controversial during an algae plague! Only by a very modest water exchange programme, would the toxic chemicals be able to build up to a significant concentration level required to pose a toxic effect._

he continues, and I wont quote it all here. I've read Walstad's book, particularly the chapter on allelopathy and I agree. She reaches way to far without proof. And we are all capable of that.

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

google a bit, theres a lot of info on allelopathy. Most will be related to terrestrial plants, and is very interesting.


----------



## ashappard (Jun 3, 2006)

chagovatoloco said:


> I haven't used a test kit in a while, don't use a ph controler and agree that ample fertilizer is a key. How ever a drop checker is a inexpensive way to get a good base line on co2. Allelopathy may not be as important as some of the books I have read have stated. As for over thinking, I'm just trying to get a better understanding of what is going on. Is that false hope?


here and on other planted tank forums, I see this quite often :

problem is observed. 
responses say "it sounds alot like something that is related to too little CO2"
then the OP responds "but my drop checker is <some color> - it cant be CO2"

thats the misuse and over-trust. 
drop checkers arent junk or snake oil, but they are only useful when applied correctly. 
place the drop checker in the plant beds. Reposition it about the tank a few times and let it settle. does the color change? As the color changes, what does that tell you? if you adjust flow and/or increase injection efficiency then what happens? doing this over and over can be tedious.

So I skip that, and go for known methods of injection that give solid results (mazzei / needlewheel mist for example). Then I incrementally add more CO2 to the point that it begins to stress the livestock, then I back off. It isnt cruel - its effective. the livestock all survive the adjustment. a good regulator/needlevalve keeps the injection rate consistent. Good flow makes sure that CO2 enriched water makes its rounds, not only at the top but in the plant beds as well. Is this a waste of CO2? not in my experience. Of course, I am one of those guys who 'waste' ferts by doing large water changes on a regular schedule 

Also I'm biased. I was dialing in CO2 before drop checkers were trendy, and after I gave up on pH controllers. So I've never really wanted one but did force myself to play with them more than once. Since I've never really believed in the need for a drop checker - take my swat at them with a grain of salt, whether I think I have a point or not.

I've got methods that I like, I make them as simple as possible and avoid complexity. That way I can keep many tanks with different parameters and still have stability without fighting the tanks constantly. Doesn't mean that everybody has to do it that way, and I do like seeing different methods. Especially ones that are demonstrated to be effective.


----------



## chagovatoloco (Nov 17, 2007)

I just like to get a base line with the drop checker. I agree that fine tuning is what is needed, I don't believe that other than the live stock excess co2 has any averse effect.


----------



## bartoli (May 8, 2006)

ashappard said:


> _A natural question to pose would be: Can allelopathy be used to control algae growth in the aquarium? The answer would be NO! One would have to advocate lowering the water exchange, which would be controversial during an algae plague! Only by a very modest water exchange programme, would the toxic chemicals be able to build up to a significant concentration level required to pose a toxic effect._


I very seldom do water change. In fact I have tanks that went for several years without any water change. May be that allowed the allelochemicals in my tanks to accumulate to a level that effectively controls algae growth?


----------



## ashappard (Jun 3, 2006)

bartoli said:


> I very seldom do water change. In fact I have tanks that went for several years without any water change. May be that allowed the allelochemicals in my tanks to accumulate to a level that effectively controls algae growth?


or use Ockham's razor, simple solution is more likely
is it easier to prove that stability and balance prevent algae, or is it easier to prove its allelopathy?

honestly - think about that. why are people reaching for explanations like allelopathy when you can do repeatable experiments showing that nutrient levels / ratios of nutrients / gasses concentration / temp etc and so forth all have an effect on stability.

It gets measured / documented / studied / discussed / there are methods - EI and PPS and many variations of each. theres 'low tech' or 'natural' tanks. Its a great branch of the hobby I really do like those kinds of tanks. the thing I notice about (my own) no-wc tanks is they are slower systems, the input is less, there is slower growth, there is usually a very good balance between biomass and light and nutrients. thats how a tank like that thrives. I have no reason to believe that allelopathy can have a measured effect there. things happen more slowly in low tech tanks, that doesn't mean that a slower version of the same system needs a new explanation for its stability.

I'd like to see some studies that measure allelopathic compounds in aquarium substrates and the water column, in filters etc. I'm surprised we havent seen a lot more discussion on allelopathy than the arguments that are saying 'maybe' and 'possibly'. Or maybe I'm not - because I have a hard time buying the concept when a simpler solution is available.


----------



## Edward (May 25, 2004)

*Can we explain this repeatable experiment?*

Fill up a smaller size aquarium with only water and no substrate just to keep it simple. Setup good light. Then maintain steady parameters 10 ppm NO3, 1 ppm PO4, 13 ppm K, TE, 25 ppm Ca, 0.1 ppm Mg, etc. the usual works we do to grow plants. In about 3 weeks time the walls will start turning green with algae. This green infested aquarium will remain until we place lots of plant mass in the aquarium. Still maintaining the steady parameters. No change, just a load of plants being added. Please note, no water changes, don't need any. Suddenly out of the blue, algae starts disappearing! Why? Any rational explanation?

*1.* It is not nutrient competition between algae and plants, because there are the same levels maintained during the test. 

*2.* It is not CO2, because there is the same amount maintained during the test. Anyway, try it with or without it, no difference.

*3.* ?

*4.* ?

Anyone else? Any ideas why the algae die?

IMO, there is a perfectly rational explanation for it. The plants release something in the environment killing the algae. What are your thoughts?

Edward


----------



## ashappard (Jun 3, 2006)

Edward said:


> *Can we explain this repeatable experiment?*
> 
> Fill up a smaller size aquarium with only water and no substrate just to keep it simple. Setup good light. Then maintain steady parameters 10 ppm NO3, 1 ppm PO4, 13 ppm K, TE, 25 ppm Ca, 0.1 ppm Mg, etc. the usual works we do to grow plants. In about 3 weeks time the walls will start turning green with algae. This green infested aquarium will remain until we place lots of plant mass in the aquarium. Still maintaining the steady parameters. No change, just a load of plants being added. Please note, no water changes, don't need any. Suddenly out of the blue, algae starts disappearing! Why? Any rational explanation?
> 
> ...


not familiar with that experiment. But it does not sound like it is designed with allelopathy in mind.

yes it is rational to wonder if plants are releasing a chemical that will suppress algae. But wouldnt a better experiment to prove this be :

take some of these allelopathic chemicals - they are known - and add them to an aquarium _having no plants_ and add them in the _same concentration_ as they are found in the control tank which does contain plants. Then observe the effect on algae in both tanks.

so its a variation on your experiment, but designed to target the idea that allelopathy can have a measured effect vs plant competition. You set up two tanks as you describe and let them get grungy with algae. In one add plants in the other add allelopathic compounds.

newly set up aquariums will bloom many things, bacteria / algae / tiny critters - so I'm not sure what the originally proposed experiment can prove besides that plants add to and aid stability in the aquatic system.

not trying to be difficult Edward, just proposing a better experiment.

EDIT :

additionally - aquatic allelopathic componds arent usually associated with 'cleaning up' an aquatic system, but are proposed as reasons why large stands of certain aquatic sp. are not covered in epiphytic algae.

I haven't seen any serious researcher propose that allelopathic compounds clean or stabilize an aquatic system - but I havent read every thing out there either. I'm still very skeptical, but will definitely remain open to any reasonable literature that really shows they can do something in our aquariums.

like another poster mentioned earlier - I'm surprised that a company has not tried to market allelopathy. As a real product or even as snake oil. Given the interest in it, it could be extremely profitable as a snake-oil product and there is ample circumstantial evidence to support wide-ranging claims of its capability.


----------



## bartoli (May 8, 2006)

ashappard said:


> or use Ockham's razor, simple solution is more likely
> is it easier to prove that stability and balance prevent algae, or is it easier to prove its allelopathy?


That is not the issue. Earlier you said:



ashappard said:


> I don't think that anybody who has debunked allelopathy believes that the effect is a myth, but that in the aquatic systems we keep its effect is negligible to the point of being a non-issue.


It turned out that the reason someone thought it would have only negligible effect was based on the assumption of frequent water change. Here is what the author himself said (and you yourself had quoted it in one of your messages):



ashappard said:


> _Only by a very modest water exchange programme, would the toxic chemicals be able to build up to a significant concentration level required to pose a toxic effect._


Tanks maintained as per the way described in Ms. Walstad's book "Ecology of the Planted Aquarium" do not go through frequent water change. It is therefore reasonable to believe that in such aquatic systems allelopathy probably contributed in some non-trivial way towards the prevention of algae.


----------



## Edward (May 25, 2004)

ashappard said:


> take some of these allelopathic chemicals - they are known - and add them to an aquarium ...


 Most of these chemicals are not known yet, there are thousands plus combinations. They are so complex organic compositions, today's science does not understand. As an example, toxic mushroom substances and snakes venom. Look at these and ask yourself, are they simple chemicals, are there laboratory synthetic equivalents available? No and very few. Scientific centers are still working on it as we speak. Aquatic plant Allelopathy is not exactly priority so we may never know.



ashappard said:


> newly set up aquariums will bloom many things, bacteria / algae / tiny critters - so I'm not sure what the originally proposed experiment can prove besides that plants add to and aid stability in the aquatic system.


 I think it can prove that nutritional competition and or CO2 levels does not apply as many sugest. My question still remains the same, what is it then? Logically, what's left?


----------



## niko (Jan 28, 2004)

I will not try to explain why good plant growth usually prevents algae from developing. But here are 2 things that I think should be mentioned in this topic:

*1. "Paranormal" plant sensitivity*
I've said that before. I used to work with indoor plants. Taking care of office plants. It's a big shadow business that not everybody knows about. As a tech you visit a number of offices around town and pretend you take some special care of the plants. So basically I saw many different environments where plants where placed. Over time I realized that plants are consistently showing better growth in offices where the people where upbeat and seemed to have good relationships. And of course the opposite - offices where people where stressed or seemed to hate each other always had problems with the plants. I asked my colleagues if they had noticed something crazy like that and everyone I asked immediately said that they had noticed that countless times. And could not attribute the issues to bad light, bad care or diseases.

What does all that have to do with aquatic plants vs. algae? It leads to item #2:

*2. In a well established tank it's actually VERY hard to bring about algae. * 
Low light, high light, reduced circulation, no more fertilizing - these things usually bring bad plant growth and eventually algae. But not in all cases. As we speak I have 2 severely neglected tanks that have 0 algae. Here's one of them:
http://picasaweb.google.com/ddasega/48T5HODIYHousing

So ugly I can enter it in a contest. Water change has not been done in about 3 weeks (the air gap is evaporation!). No ferts for about 45 days now. The Chinese filter fills with air and the flow has been about 50 gph for weeks now (supposed to be 300). I feed the fish very little 2-3 times a week. The floating mass of plants was added about 2 weeks ago. Before that the tank had a clear surface for about 2 months and was bright enough to grow downoi on the bottom. There where no algae when it was bright. There are no algae now - open surface of cluttered surface.

I have had tanks like that before. I think that there is a *connection between (1) and (2)*:

The plants have some way of suppressing algae that is not chemical. If the warfare between plants and algae was only chemical then every time I neglect my tank I'd have algae. It's almost as if the plants claim the territory and algae clears the grounds. Algae seem to be able to do the same too. From what I just wrote it seems that there is more to things like ADA's Tourmaline and the crazy sounding Plocher system.

And definitely there is a lot to be said about the definition of "well established tank" - all the tanks that I've had 0 algae no matter what I did always had a VERY long period of initial establishment. For example that 55 on the link above ran with no light, no plants, no CO2, just filter and heater for about 5 months. (That's one of the reasons I consider Tom's EI a method of stunning the tank's natural development. Basically artificially keeping the tank in an "adolescent, fast growing phase". EI grows plants like crazy. But stop the water changes and heavy fertlizing in a beautiful healthy EI tank and you will get algae, guaranteed.)

And since this topic is about the connection between NPK and lack of algae growth:
For me *Macronutrients, added in the proper phase of the tank development*, serve to cement the establishment of plants as the undisputed dominant group. They should not be used as a crutch to maintain healthy plant growth. If your tank turns into an algae heaven once you stop adding NPK then your system is not correctly established to start with.

--Nikolay


----------



## ashappard (Jun 3, 2006)

okay I see whats going on here.

I'm going to skip the paranormal stuff niko -- too easy, and also pointless to attack it.
I've also heard people respond affirmatively to the suggestion that chi flows all around us.  that the arrangement of furniture or the flow of a garden channels energy. I'm not touching that. Its an unwinnable argument for me, and pointless to try.

edward -- Allelopathic chemicals are not mysterious and elusive. I still haven't seen any _serious_ suggestion with actual evidence that they have any effect whatsoever in an aquarium. A stable aquarium does not prove Theory A/B/C unless evidence is collected showing an _actual _ connection. Repeatable evidence. With measurements, and results that can be duplicated. Allelopathic compounds are known to exist in measurable quantities in certain sp. -- why not farm those, make an extract, test it? I know, I know - its way more complex than that.

you hit on something here :


> Aquatic plant Allelopathy is not exactly priority so we may never know


agreed. Got an idea why its not priority?
There has been research. It failed to prove that the effect is significant, that it has any significance in aquaculture or weed management. Doesn't mean it wont be someday, but I'm not holding my breath.

niko -- aged tanks can be created with any method. Digging up Tom is a strategy in a lot of threads - he has fanboys / he has detractors. His opinions are used both to prove and disprove points on freshwater aquariums. EI and PPS systems are variations of each other and neither is original (so odd that fights break out over which is better), both require input or they spin out of control. We've all heard/seen/read about or even had our own tanks that are amazingly stable with 'no help' whatsoever. Something in that system is being consumed, so there is input, its not frozen in time.

No matter how slow, fast or amazingly stable there is still a driver doing something keeping stability on track. A well crafted custom substrate can be a driver, those are becoming pretty popular. Not every system has to involve the water column exclusively.

I offer this as a suggestion :

say that I'd never heard of Tourmaline / Penac / some other future voodoo magic.
say I'd never heard of the vibrations, oscillations, ionizations and stuff that sounds like a late night infomercial more than science.

say I also happily manage my tanks without considering Allelopathy, instead I focus on light, flow, nutrients and biomass. Now I know that it sounds silly - but I can still manage a stable tank and I can control the stability. I know what I did and what I will do to maintain stability. sometimes its a lot sometimes its a little. sometimes it works out better than I expected, sometimes worse. but I take notes, lots of notes, I compare observations, I do _A _and _B _happens. Its not mysterious, and I don't want it to be. Aquatic systems are interesting and beautiful without mystic forces.

just because you may not be able to put your finger on what makes a system stable, that doesnt mean that Santa Claus is keeping it stable because you have been a very good boy this year.

I'm switching back to lurking mode. nighty nite!


----------



## ashappard (Jun 3, 2006)

bartoli said:


> Tanks maintained as per the way described in Ms. Walstad's book "Ecology of the Planted Aquarium" do not go through frequent water change. It is therefore reasonable to believe that in such aquatic systems allelopathy probably contributed in some non-trivial way towards the prevention of algae.


ok, one more -- Bartoli you are stuck on the water change thing, and I did quote that so my bad. But there is more to Pedersen's article.

So the challenge is to isolate what it is about this no-wc system that is making it stable. If it is Allelopathy, measure it and prove it is having a greater effect than the natural cycle of nutrient exchange/conversion when it comes to algae control. Or even show that it has an effect at all, measure it somehow and isolate the effect from others in the same way we can vary nutrients, light, flow and measure the effect.

do you guys even know if the plant sp. you keep are creating Allelopathic compounds? do they interact / cancel / how long do they last / are they in the substrate, filter, water column? too sketchy..

I know how to set up / age and maintain a stable no-wc tank. Its not a difficult process and lots of people know how to do it. Like cookie cutters the world is peppered with these mysterious no-wc wonders. They are not dominated by Allelopathy. They are not influenced by Allelopathy in a measurable repeatable way. _prove_ that they are, publish it, I'll give you a crisp $100 bill.

on topic kinda -- "the Happening" worst movie so far from an increasingly lackluster M. Night Shyamalan

I'm going to go sing to my erios now. If they know they are loved, perhaps they will not hold a grudge when I take the blade to them.


----------



## Nelumbo74 (May 2, 2008)

I have read that common anacharis (Egeria densa) has allelopathic characteristics. In fact, if you Google "egeria densa allelopathy", you'll find many entries, including a reference to a past article of the Aquatic Gardener. I am not familiar with any other aquatics that are known to have these same characteristics.



hoppycalif said:


> Yes, you can find a lot about allelopathic chemicals, but it is always about terrestrial plants, and only a few of them. I have never found any article about such chemicals coming from aquatic plants. Even Tropica did some work on that, but ended up saying aquatic plants probably don't produce them. http://www.tropica.dk/article.asp?type=aquaristic&id=531 Still, the test I mentioned should demonstrate that they are present, if they are.


----------



## Edward (May 25, 2004)

ashappard said:


> agreed. Got an idea why its not priority?


Researching planted aquarium allelopathy for few hobbyists who know about it doesn't justify the cost when there is a market for other more attractive goods. If I think about it what has the industry provided us with as far as production line goes, it is rather sad. I've been watching it for about 3 - 4 decades now. The industry is years behind the knowledge of an average to advanced hobbyist. New aquarists are blasted with tons of stuff they never need and that is the goal of today's economy. 

Nonetheless, neither of us can provide an evidence to support a theory why is allelopathy or 'something' else happening the way it is. 

Thank you all


----------



## ashappard (Jun 3, 2006)

Nelumbo74 said:


> I have read that common anacharis (Egeria densa) has allelopathic characteristics. In fact, if you Google "egeria densa allelopathy", you'll find many entries, including a reference to a past article of the Aquatic Gardener. I am not familiar with any other aquatics that are known to have these same characteristics.


and hornworts and mirios and over a dozen other sp.

what's missing is proof that this allelopathy has a significant, measurable effect in the aquariums we keep. From Diana's natural aquariums to niko's ignored wundertank. If you read closely, allelopathy is overwhelmingly connected to the shrugging off of parasites and epiphytes. Also it often comes up that allelopathic warfare is plant-to-plant. Somebody seize on that, and blame macrophyte _A _for the demise of _B_ in your aquarium.

Allelopathy exists, but its a stretch to say it maintains or contributes to stability in a no-wc system or any other of the many freshwater systems we maintain. measure it. demonstrate it. somebody.

ok, now I promise - back to lurking.
not before I mention that substrate heating cables didn't come up once in this thread unless I missed it. Years ago it would have been the hot button. "it works" / "it doesnt work" / "prove it" etc and so forth ad nauseum


----------



## BryceM (Nov 6, 2005)

To leave the allelopathy discussion for a moment, a historical perspective maybe provides some insight into the OP's question. In the early days of planted aquariums, we did not possess the high-output lighting systems that are popular today. At that time, I don't think anyone was actually adding macronutrients to a planted aquarium. Suggesting the idea would have seemed ridiculous. Despite that, there are examples of gorgeous aquariums from the period with no noticeable algae.

Skip forward and we're now using high-light, CO2-driven systems. Plant growth in such conditions can be nothing short of stupendous. It's probably unusual for these plants to reach the fullness and vigor that they achieve in our "modern" glass boxes.

We can see that plants are widely adaptable to a number of conditions. Different leaf types are seen in emersed vs submerged settings, for example. These adaptations are not instantaneous. It takes a few days for the physiology to "catch up" with new conditions.

Now, imagine plants that are growing at maximum speed in ideal circumstances. Now imagine a sudden shortage of a key nutrient. It's my opinion that this results in a sudden and dramatic deterioration in plant health. Once the plants stop growing, algae (for whatever reason) get a foothold.

In a nutshell, low-light systems tend to remain algae-free. High-light systems without CO2 and macronutrient addition always fail miserably. You have to match your nutrients to the particular setting. Once you have the correct balance of light and CO2 it's a simple matter of regular dosing of macros & micros. The exact quantity is far less important than dosing discipline. A sudden "crash & burn" is what you're trying to avoid.


----------



## Avalon (Mar 7, 2005)

I think we all come into our own as we grow in experience with planted tanks. We have our logic and reason behind our techniques, and there is no one right way to do things. I take a natural approach. We all try so hard to replicate natural systems in our tanks, but the fact is, we don't and we can't. Natural systems vary greatly, but as responsible plant keepers, we know that in many ways we can provide better conditions than certain bodies of water.

I once had a dream that the only thing that mattered in our short lifetime was life itself, and when you realistically look at nature, that's exactly what you'll find even in the most disparaging of conditions. It's not always as pretty as we might imagine, but it's happening, all at its own pace.

You probably have in mind a few aquariums that have inspired you, given you a new perspective, or have simply made you think "wow, that's nice." What do you see? A clean tank with no mulm build up in corners, no dead leaves floating about, but most noticeably, a well maintained aquarium. Nutrients are an elementary factor in planted aquariums; it's how we tend to that environment that influences the outcome. Too many people obsess about their lighting, substrates, and fertilizers to realize that maintaining the environment is among the most crucial of factors. Many simply can't see the forest for the trees. What is left after you've provided for the plants' needs? In your own home you can have your pantries fully stocked and eat like a king, but if you don't clean up after yourself, you're bound to see mice, cockroaches, ants, and other nasty little scavengers ready to take advantage of your sloppy conditions.

So give the plants some food, the light they need, and be diligent about keeping the aquarium environment clean and the plants well groomed, and you'll reap the rewards: healthy plants free of algae. It really isn't more difficult than that.


----------



## Cavan Allen (Jul 22, 2004)

♦ You're right, it really isn't all that difficult. But I think a lot of the discussion here is fueled by fascination with the How rather than the Why. I may be wrong...


----------



## Avalon (Mar 7, 2005)

The "how" has already been explained many times over. It's most often the "why" that gives most people the problems. If you're looking for a quantitative "how," then good luck. We're just trying to grow healthy plants.


----------



## Cavan Allen (Jul 22, 2004)

OK, my previous response wasn't worded or presented very well so I'll give it another shot. It seems like you're basically saying "why ask why" to the question posed in the thread title; lots of people know what to do to grow healthy plants and prevent algae. The discussion here seems geared towards understanding the mechanisms by which algae is prevented. Everyone involved in this thread could very well go about growing healthy plants and not delve into why what they're doing works. Some of us choose to do so anyway simply for the interest factor.


----------

