# healthy plants = no algae WHY??



## Hyzer (Mar 9, 2010)

I'm a noob, but i read that co2 shortage brings on algae most of the time. Did you increase carbon availability?


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## StaleyDaBear (Apr 15, 2010)

+1 to lack of co2 comment. Pressurized co2 changed my life . . . *tear*


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## fooledyas (Feb 22, 2010)

I had no algae with diy co2 and I still have no algae with pressurized co2. So maybe co2 is right but what I'd like to know is if I don't change anything : ferts, co2 or light and i take all the plants out would i still be algae free


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## jargonchipmunk (Dec 8, 2008)

if you change nothing else, then no. you'd have great success at algae farming. You'd take out the plants that would be taking up the nutrients you're providing, but still adding all those nutrients.


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## Wasserpest (Jun 12, 2003)

fooledyas said:


> I get that healthy plants mean no algae but I want to understand what is about plants that prevents algae. I've read that the plants take up the nutrients that the algae feeds on but that cant be right with all the phosphates and nitrates I dump in the tank there should be plenty to go round. Can't be the light I went from 20w T12 to 96w T5ho plenty of light to go round. It obviously works. my results are great, I just want to understand why


It's really one of the great mysteries of your hobby why a tank full of healthy growing plants repels algae. 

Some suggest "outcompeting" which obviously isn't the case since we have nutrients in excess, and algae have relatively sparse requirements.

Others blame "allelopathy" where plants exude some complex substances that give algae a hard time, similar to antibiotics killing off bacteria. While common in terrestric environments (soil), it is hard to prove or disprove when moving water is involved.

I think algae are a bit more picky in their requirements than we assume, while higher plants are astonishingly adaptable. Vigorous plant growth causes - for example - high levels of oxygen, up to saturation. Could be the daily fluctuation, or the absolute level, that makes it difficult for algae to adapt. Of course this isn't the case in all algae free tanks, their could be many other reasons for example in low tech tanks.

We know that the presence of flourishing plants creates an environment that isn't promoting algae, and just like with the extinction of dinosaurs -- even if we are not sure about the exact reasons, we enjoy the results. roud:


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## fooledyas (Feb 22, 2010)

jargonchipmunk said:


> if you change nothing else, then no. you'd have great success at algae farming. You'd take out the plants that would be taking up the nutrients you're providing, but still adding all those nutrients.


 
I get that the plants are taking up the nutrients but with EI there's no shortage of nutrients. Even at the end of the day after the co2 and lights have been cranking out for ten hours my nitrates are at 20ppm and phosphates are 4ppm so no shortage why then no algae. I'm really trying to understand what it is about the plants the keeps the algae in control is there a nutrient that the plants suck up that we aren't dosing in almost unlimited supply


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## fooledyas (Feb 22, 2010)

Wasserpest said:


> It's really one of the great mysteries of your hobby why a tank full of healthy growing plants repels algae.
> 
> Some suggest "outcompeting" which obviously isn't the case since we have nutrients in excess, and algae have relatively sparse requirements.
> 
> ...


 

Thank you thats what I was trying to get at. No answer is something I deal with often at work I do repairs on very complicated machines and very often I know a part is bad even though I have know idea what it does or why its bad. replacement=solution. It's the things I don't know that are knowable that really bug me


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## tuvix72 (Dec 16, 2003)

Wasserpest said:


> It's really one of the great mysteries of your hobby why a tank full of healthy growing plants repels algae.


Agreed. We have been asking ourselves this forever!

We've had periods of 'enlightenment' here and there... from absence of deficiencies when PMDD/EI was introduced, to allelopathy when Diane's book came out... to oxygen levels when pearling became the big goal for everyone... today it seems light & CO2 to be under closer scrutiny than in the past.

Allelopathy and oxygen levels are something that the plants cause themselves as a direct consequence of their well being... light, nutrients and co2 are what make the plants grow well. Either there is a relationship between algae growth and the environment they are in (plants excluded), or there is a relationship between algae and the well being of the plants and their overall mass. Or a mixture of the two? :biggrin:

My money is in either a mixture of the two or a direct connection with the plant's motabolism, I can't see it being solely an environmental thing.

Regards,
Giancarlo Podio


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## farmhand (Jun 25, 2009)

Wasserpest said:


> I think algae are a bit more picky in their requirements than we assume, while higher plants are astonishingly adaptable. Vigorous plant growth causes - for example - high levels of oxygen, up to saturation. C


This test would be beyond my abilities, but if you could hook up an oxygen tank and mix it like we do CO2, you could rule out if high oxygen had anything to do with it.


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## tuvix72 (Dec 16, 2003)

farmhand said:


> This test would be beyond my abilities, but if you could hook up an oxygen tank and mix it like we do CO2, you could rule out if high oxygen had anything to do with it.


I actually tried this a couple years ago, I was unable to see any benefits beyond 'morning pearling'... 

Regards,
Giancarlo Podio


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## Wasserpest (Jun 12, 2003)

Don't think for a moment that I suggested hooking up an O2 tank will have any benefits to your planted algae-infested aquarium. Re-read what I wrote... it's just an example for a set of conditions that are really much more complex.

I am sure there is some alga that will react very negatively to added O2... that still doesn't explain the whole phenomenon. So if you quote this out of context it will look completely false.


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## fooledyas (Feb 22, 2010)

I guess we'll just have to be thankful it works. We can test the theory's we can and hope someone tests the theory's we don't have the resources to check . For those of us who have a real need to know how things work (like me) we'll just have to wait


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## mistergreen (Dec 9, 2006)

Hi folks,
I'm dropping in from Connecticut. 

Another explanations is the presence of NH4 (ammonium) however small. It's well known that NH4 will trigger multiple algae. A heavily tank stocked with fish will most likely have more algae issues than a lightly stocked tank given same parameters.

A tank full of plants will soak up any NH4 before it has a chance to trigger algae.

my 2 cents.


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## farmhand (Jun 25, 2009)

Wasserpest said:


> Don't think for a moment that I suggested hooking up an O2 tank will have any benefits to your planted algae-infested aquarium. Re-read what I wrote... it's just an example for a set of conditions that are really much more complex.
> 
> I am sure there is some alga that will react very negatively to added O2... that still doesn't explain the whole phenomenon. So if you quote this out of context it will look completely false.


I wasn't suggesting you thought this. Only was adding O2 to the list of variables to try to understand what is not understood. (At least what I do not understand.) I apologize for any misunderstanding.


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## fischman (Feb 22, 2010)

mistergreen said:


> Hi folks,
> I'm dropping in from Connecticut.
> 
> Another explanations is the presence of NH4 (ammonium) however small. It's well known that NH4 will trigger multiple algae. A heavily tank stocked with fish will most likely have more algae issues than a lightly stocked tank given same parameters.
> ...


This seems to make sense to me. I'd be curious to see a test with a NH4 deficient tank versus one with lots of NH4 (of course no critters living in there). And see what the difference would be in algae. This would appear to be the one thing that plants, especially when fed lots of light/CO2/Nutrients would rapidly remove from the water and thus stifle the algae growth. Very interesting...

Josh


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## hbosman (Oct 5, 2006)

"allelopathy" wouldn't exactly explain it either since 50% water changes would negate any chemical the plants could excrete in any significant amounts. Just imagine putting a glass of water in the window sill without any chemicals. It will promote algae so, plants limiting chemicals in the water wouldn't explain why heavily planted tanks don't have algae. I know healthy, fast growing plants tend to resist algae. So I sure would like the answer to this question as well.


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## Elohim_Meth (May 8, 2010)

I doubt the NH4 algae trigger theory. It sounds good but...
When I started a tank with AquaSoil, three weeks or so there were about 3 ppm of NH3/NH4, full light from 3 to 6 hours a day gradually increased and lot of plants. Still no algae.
On the other side, TPN+ contains Ammonium nitrate (NH4NO3) as a sole source of nitrogen. A lot of users and a lot of good feedback.
I think it is still (and a way long will be) beyond our knowledge, why healthy plants outcompete algae. I guess it has something to do with what mystical minded people call 'biofield'. But I hope someday we will learn the truth.


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## fooledyas (Feb 22, 2010)

we'll just have to chock it up to F.M.


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## StaleyDaBear (Apr 15, 2010)

This has been a really interesting thread. My one and a half cent(s)? How many of us stock algae eaters? If they were gone, would algae be as prominent without them? Case in point : My breeding pair of angels are highly terretorial when eggs are laid, and let nothing, repeat NO THIN, even my snails to come near it. Now, on my amazon sword I can see a small bit of thread algae building on a few of the leaves, but my othe amazon which is on the opposite side of the tank, is algae free. It's just like in large ecosystems where humans who think they know what they are doing, introduce algae eating fauna to lakes which get overrun with algae due to pollution. But I digress . . . I am in agreeance with everyone, that it must be much more complicated then just one answer, or just ten answers.


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## fooledyas (Feb 22, 2010)

StaleyDaBear said:


> This has been a really interesting thread. My one and a half cent(s)? How many of us stock algae eaters? If they were gone, would algae be as prominent without them?


 
They may be the cause in some cases like the one you stated but I don't have any algae eating fish. But since i added plants ferts,& co2 i have a lot less algae than there was in the same tank with same fish for the last 10 years. seems to me that many great points wave been made here and maybe they all add up to an answer. 3 or 4 or 5 or 6 things done right= no algae. Different combinations for different situations. That what I get out of this thread. thankyou all for your great responses


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## plantbrain (Dec 15, 2003)

Well folks do clean the algae off, they do prune and remove older leaves, they do add algae eaters, they do use lower light etc.

If they have more light, they generally add more CO2.

But adding CO2 is not why algae do not grow:









No CO2 added there.........


A better question is: "Why does algae not out compete itself, or other species of algae then?"

What mechanisms would it possess to allow it to complete its life cycle in a specific niche?

This has little to do with aquarium competition and much more to do with eking out survival in natural systems. Aquariums are long way from anything remotely "natural".

I'm surprised we do not have far more species bothering up than we do.
Many you never see BTW. Too small for the naked eye. I've added O2, back maybe in 2002? This does nothing to algae biomass per unit area.

Allelopathy somehow always comes up and simply will not die as some cause 
Large water changes, activated carbon which many have used for a very long time removes these very same allelopathic chemicals. AC is actually used in allelopathic controls for references in research. Then we have wide range of species, maybe 300-400? what are the odds that they all possess 
the same allelopathic anit algae chemicals that they release into the water?

A few billion to one.

Not good odds.
Those are my main two, one is a test that would predict algae blooms if the allelopathic chemicals are removed if the hypothesis where true. Basic experimentation that most any aquarist can do. Then you have falsified one big step of the hypothesis, it's not looking good after that.

Next look at the various compounds that plants give off that are considered allelopathic, there's a lot of different ones, and each species produces different ones etc. Why would an aquatic plant even need these in a natural system? Most plants that grow submersed year round grow at much faster rates than algae can colonize. The others, maybe 80% of the species we keep, grow most of the year emergent.

Why do we not see plant- plant allelopathy?
Never seen this once or even anything close to it.
Again, activate carbon would remove it if it occurs.

Now..........what about plant - plant competition for nutrients? Light? and the biggy........CO2?

Why do not folks carry on about that?

Algae is interesting, but there is very very little real knowledge known about the very basics, the life history of most are simply blank in the research, some stuff, not much is there. Aquariums vary greatly also, so does the care and light/CO2 etc.........

Still, the focus really is growing aquatic plants, that's the main issue and not doing that leads to algae issues. That's about as general a reason as to "why" as any simple answer will get you.

Now if you like to grow specific algae, then that's another question.
I think many folks toss manure out there without testing much and as a result, get nowhere fast. NH4 induced algae under very high light and when the CO2 was modified also. Under low light, it does not.

Leaving little tid bits out of the entire picture often leads to mistinformation also. Folks just read one part, not the part that suggest it's speculation etc.
We can test and test...but all it takes is one experiment that can prove us wrong.

That's what happened to PMDD, even though it helped put most of the pieces together how to grow aquatic plants cheap with ferts on the web.

Regards, 
Tom Barr


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## fooledyas (Feb 22, 2010)

plantbrain said:


> Still, the focus really is growing aquatic plants, that's the main issue and not doing that leads to algae issues. That's about as general a reason as to "why" as any simple answer will get you.


while I agree that the focus should be on growing healthy plants. The "why" is based on curiosity and a desire to know how things work. When I talk to others about adding nitrates and phosphates they look at me like I'm nuts. For years we all thought this would lead to algae. A small fortune has been spent over the years by me and others to remove these from the water only to find out they are not problem, It would be nice to be able to say something other than i dont know why it works but it does when telling people of my new found success with keeping algae at bay with plants.


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## Elohim_Meth (May 8, 2010)

Tom, did you induce algae on purpose by adding NH4 in planted tank?


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## TheVisionary78 (Mar 6, 2010)

My theory is that plants are picky. They pick and choose which elements and which ferts they want at that perticular time. So us as hobbiest we follow instructions. Like dose 5ml per week ect..... Well most of our ferts have other ingredients like copper, mag, ect..... These can build up. Algae will feed off of anything excess. We as hobbiest like to blame phostphorus and phosphates but we might want to start looking a little deeper into what algae is. A cingle celled organism that feeds off of excess nutrients in the water. 

An old friend of mine who has been in the hobby for over 40 years way before high output lighting told me something once. "Keep it simple stupid". Unplug all that crap and just let the plants do their job. He was old school. Cheap plastic corner filter and that was it. But he used to get the most lush growth in history. He used to keep his tanks in a green house. No thermometer. No lighting besides the sun. Limited filtration. Light fish volume.


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## fooledyas (Feb 22, 2010)

TheVisionary78 said:


> will feed off of anything excess. We as hobbiest like to blame phostphorus and phosphates but we might want to start looking a little deeper into what algae is. A cingle celled organism that feeds off of excess nutrients in the water.
> .


If the algae feeds off excesses then EI wouldn't work. we add way more nutrients then the plants consume in most cases


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## plantbrain (Dec 15, 2003)

fooledyas said:


> while I agree that the focus should be on growing healthy plants. The "why" is based on curiosity and a desire to know how things work. When I talk to others about adding nitrates and phosphates they look at me like I'm nuts. For years we all thought this would lead to algae. A small fortune has been spent over the years by me and others to remove these from the water only to find out they are not problem, It would be nice to be able to say something other than i dont know why it works but it does when telling people of my new found success with keeping algae at bay with plants.


Their own assumptions make them think this way, not the observations.

While it might be nice, life ain't nice nor is it's reasons easy to figure out, or how, when, where, or why.

What you can do to those that claim something is caused by X........is test just that, and see if it holds true or not. Even Einstein said all the theories and test he did could be proven untrue by just one person/test, but nothing he's tested could prove him right. 

Folks have to live with some uncertainly. Many do not like that, but really they know much less than they like to think they do. A wise person is aware of their ignorance, a fool is not. I know a lot more about algae that many a fool, but then again, I do not know that much. I got plenty of questions, we all do, so folks can start by setting up test and seeing what they can answer and test.

We already know about plants being able to dominate algae, see Bachmann et al, 2001.

Regards, 
Tom Barr


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## plantbrain (Dec 15, 2003)

Elohim_Meth said:


> Tom, did you induce algae on purpose by adding NH4 in planted tank?


Yes, but under very high light in a shallow tank, I only got Green water.
So that's specific. It's not really a general theory, mechanism for algae blooms.
We also see GW in new aquariums without good plant biomass or bacteria, but...........we also rarely see algae in ADA AS tanks also.

These leach high NH4 for a month or so.

Perhaps the tannins prevent Green water, generally, ADA tanks have about 1/2 the light in terms of PAR you might think they do also.

I used NH4Cl.
I also used Jobes sticks.
I also over loaded the bioload by adding too many fish till algae bloom occurred.

All cases used 160 micromols of light at the bottom and 450 at the surface. 

Regards, 
Tom Barr


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## plantbrain (Dec 15, 2003)

TheVisionary78 said:


> My theory is that plants are picky.


Wouldn't be that algae are picky and not plants?
Plants need more.

Like mice and elephants, both are herbivores, but mice can colonize more niches ecologically than elephants. Elephants need a lot more food.
One elephant on 10 acres does not look like a lot, 5 tons of mice looks like a plague.

Do they really compete?
Not much.



> They pick and choose which elements and which ferts they want at that perticular time. So us as hobbiest we follow instructions. Like dose 5ml per week ect..... Well most of our ferts have other ingredients like copper, mag, ect..... These can build up. Algae will feed off of anything excess.


You mention these can "build up". How much? What does it take to induce algae then? Give me some ppm, something to support this statement.
Have you tested this or something?
I have.



> We as hobbiest like to blame phostphorus and phosphates but we might want to start looking a little deeper into what algae is. A cingle celled organism that feeds off of excess nutrients in the water.


So you seem to suggest that mice need less than elephants in terms of food?
Does this make sense? Is the nutrient demand for a billion cell complex plant less than that of a few cell algae colony?



> An old friend of mine who has been in the hobby for over 40 years way before high output lighting told me something once. "Keep it simple stupid". Unplug all that crap and just let the plants do their job. He was old school. Cheap plastic corner filter and that was it. But he used to get the most lush growth in history. He used to keep his tanks in a green house. No thermometer. No lighting besides the sun. Limited filtration. Light fish volume.


But what aquascaping skills does that method provide? Was he growing lots of Starougyne, S Belem, P stellata? what you state is true for easier aggressive weeds, emergent plants also. 

Also, few fish, this is typical for many, but I have high fish loads.
Many folks want to garden more and do not want to wait around for the plants to grow slow. Anyone can set up a non CO2 tank and have it do well.
However, in both cases, the nutrients are sky high and no algae.

Non CO2 or CO2 enriched systems can have very high nutrients.

You get much more growth per unit of energy used using CO2 however, 3-10X more, perhaps more with some species. Sunlight? then wasted light is no biggie, but indoors? Then it's more efficient to use CO2.

Comparing Apples to Oranges??
What species, and how the tank looks, and what can be done horticulturally are important oversights to such observations. you need to include them and see how fast the plants grow, measure the actual light, list the species, etc.
Not looking at it holistically will lead to poor assumptions and conflict rather than a more general approach and understanding.

Plants easily grow under a wide range of conditions, their rates of growth may change, but they still do in fact grow.........

See Tropica's article on Riccia and CO2/light interactions.
It details out a number of wide ranging treatments of light, CO2 and how the plants grow/respond. Light and CO2 can be limiting factors as well to plant growth, and thus also affect nutrients.

Regards, 
Tom Barr


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## Elohim_Meth (May 8, 2010)

One consideration just came to my mind. Some kinds of algae can consume dissolved organics, large organic molecules that plants definitely can't make use of (not before bacteria recycle it into minerals). I know BBA and BGA can do that way. Maybe other algae have something to do with dissolved organic waste as well? For example, often bacterial bloom ends up with green water.
Perhaps that is why we can't induce algae deliberately by adding minerals?
And when plants don't feel good, they are slowly degrading and leaking organics into water...


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## defdac (Dec 28, 2003)

plantbrain said:


> Even Einstein said all the theories and test he did could be proven untrue by just one person/test, but nothing he's tested could prove him right.


This is a seriously important concept.
http://en.wikipedia.org/wiki/Correlation_does_not_imply_causation



plantbrain said:


> We already know about plants being able to dominate algae, see Bachmann et al, 2001.


http://fishweb.ifas.ufl.edu/Faculty Pubs/CanfieldPubs/LimitFact.pdf
(I think he is the only author, so no "et al")


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## fooledyas (Feb 22, 2010)

defdac said:


> This is a seriously important concept.
> http://en.wikipedia.org/wiki/Correlation_does_not_imply_causation
> 
> http://


Great link thanks


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## wearsbunnyslippers (Dec 6, 2007)

i had my 100l setup last year, i was moving so i gave all my fish away as a start.

i had a huge java fern attached to a piece of driftwood.










this tank was algae free for months, no excel, co2 or ferts. substrate was tetra plant substrate capped with inert black sand. i then took out the java fern. and i starting getting algae.

java fern was attached to wood which was removed, the substrate wasnt disturbed. nothing else changed, no fish, so no waste or food, no ferts, the lighting stayed the same. 

so why algae all of a sudden?


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## fooledyas (Feb 22, 2010)

wearsbunnyslippers said:


> i had my 100l setup last year, i was moving so i gave all my fish away as a start.
> 
> i had a huge java fern attached to a piece of driftwood.
> 
> ...


were you doing water changes that could be your source of ferts that without the plant were there to feed the algae


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## plantbrain (Dec 15, 2003)

wearsbunnyslippers said:


> i had my 100l setup last year, i was moving so i gave all my fish away as a start.
> 
> i had a huge java fern attached to a piece of driftwood.
> 
> ...


You will grow something in there, but you removed all the plants, or most of it, many experience this same thing if they prune too much etc.

You suddenly shock the system, the CO2 goes up, the NH4 goes up, higher current, you pull up muck and spores. All good signals for germination if you are an algae spore.

The plants are taking up lots of CO2/NH4/nutrients.
Suddenly removing that is a big change and the bacteria and other processes cannot respond immediately. So algae takes hold and sticks around. Why not? Plenty of light/nutrients/CO2 and not much else to stabilize the system.

Aquatic plants stabilize most systems, removal destabilizes them.
If you have invasive aquatic weeds, this can destabilize as well, but most natural systems do not have this issue.

It is when people come along and destabilize the system, remove the plants, or dump a lot of waste suddenly, add invasive weeds, change the nutrient routines etc etc..........that there are issues. 

Regards, 
Tom Barr


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## plantbrain (Dec 15, 2003)

fooledyas said:


> were you doing water changes that could be your source of ferts that without the plant were there to feed the algae


No, in non CO2 aquariums, folks rarely if ever do water changes, that's the premise and method actually. But the result is the same either way and has little to do with nutrients. 

Sudden shifts, say in CO2 seem to have the most profound effects, but once stabilized and you still have good plant biomass, the algae has done it's life cycle and waits for the next destabilization event.

And aquarist love to mess and destabilize their planted tanks:biggrin:
So algae is common.

It's better to think what causes the germination of an algae spore, not just the old myth based classic narrow nutrient viewpoint. This is/has been easily falsified. Yes, there's a lot folks, myself included(but I'm wise enough to admit it) do not know about the algae. There might be a number of ways to induce algae, but few aquarist attempt this on purpose. That's about the only way to verify it.

Still, for management sake, there's some simple methods that can avoid it.
Non CO2 planted aquariums tend to rarely have algae issues.
Lower light + CO2, rare and less intense algae. Good general care, pruning, upkeep= less algae. Good observations by the aquarist etc, and taking care of the plant's needs, not worrying about algae 

Most of it is basic stuff.

Regards, 
Tom Barr


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## fooledyas (Feb 22, 2010)

plantbrain said:


> Sudden shifts, say in CO2 seem to have the most profound effects, but once stabilized and you still have good plant biomass, the algae has done it's life cycle and waits for the next destabilization event.


It's like the old saying nothing good happens fast in an aquarium.


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## plantbrain (Dec 15, 2003)

fooledyas said:


> It's like the old saying nothing good happens fast in an aquarium.


Not just in aquariums, but in natural systems in general concerning plants as well.

Certainly rapid changes in plants in our tanks causes large issues.
Algae have been well adapted to such rapid changes/seasonal shifts.

And like terrestrial analogies, say annual plants vs say perennial plants, algae are very much like annual plants with their spores and various life cycling stages. So they just try and germinate, complete their life cycle and back to normal unless the aquarium is bobbing back and forth. But unlike many species of plants, algae are very poorly researched and studied.
We have about 10 species that cause Planted aquarist issues.
Not bad given the total number.

Still, chronic algae aquarist...........you know the folks, they always have algae.........and then the folks that rarely get algae issues........if each has say 5 aquariums, now we can get some stat's and then they can compare, but if they only have 1-2 tanks, then it's harder to see.

I have some tanks, that never have issues, others are more pesky and require more fiddling and adjustment, equipment replacement/swapping etc.
So simple tank to tank variation, having nothing to do with my routine, nutrients, light, sediment etc, plant species, *can play a large unknown factor *. You will never answer all the questions about algae. 

But by looking at the more likely candidates, and ruling and testing each potential cause, we get closer to answers.

We move on and then go to the next candidate to test.

Regards, 
Tom Barr


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