# What causes cyanobacteria?



## Jorge_Burrito

maknwar said:


> My 40B keeps breaking out with cyanobacteria. What would cause this over and over? I've got an Eheim 2217, co2, medium lighting. Only thing that is different in this tank is that I use ada Amazonia as a substrate.


Low nitrate levels or not enough circulation often seems to get the blame.


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## ua hua

Jorge_Burrito said:


> Low nitrate levels or not enough circulation often seems to get the blame.


I have heard this same explanation of low nitrates causing BGA but really wonder if the low nitrates are more the effect of the BGA rather than the cause as the cynaobacteria actually use up all the available nitrate which would give you low nitrate readings when your system is being affected by the BGA.


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## 150EH

I don't believe the low nitrates or poor circulation, I think it is a bacteria that you need to kill off and it can be introduced through new plants, fish, etc. I just had it for the first time in a very old established tank and had to use Erythromycin too get the job done.

I noticed the top inch of my substrate (Flourite) had a white substance that was not there before I killed it off but I think it settles in to these low oxygen areas and robs O2 from the plant roots, I was having trouble growing S. porto velho prior to the Cyano but after the treatment it took off and grew like crazy and a couple other plants showed marked improvement. It also only collected on Riccia, Fissidens, and other mosses in my tank. I'm sorry to hear your having this problem over and over, this is some stinky stuff.

I am certainly no expert but these were my observations.


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## m00se

Sunlight and warm color temp lights have been implicated. Even a short duration of sunlight on the tank can make it take off. Erythromycin is the best way to completely get rid of it.


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## Wyomingite

maknwar said:


> My 40B keeps breaking out with cyanobacteria. What would cause this over and over? I've got an Eheim 2217, co2, medium lighting. Only thing that is different in this tank is that I use ada Amazonia as a substrate.


High phosphates are the primary cause, but high nitrates also contribute. Cyanobacteria do not need much light.

I'm on well water in a subdivision built on old farmland. My water is occasionally high in phosphates and nitrates, and phosphate levels and subsequent cyanobacteria blooms seemed to come in conjunction with wet weather. Makes sense, since water drains into the aquifer, taking phosphates and nitrates accumulated in the ground from decades of farming with it. I had this problem with almost every tank for over a year initially, until either algae or plants became established. Needless to say, I'm a little less meticulous about algae than I used to be when I lived in town, especially in my non-planted, cichlid tanks.

Erythromycin will kill it, and is good for the occasional or one time outbreak. But since this a continouos problem in this tank, it doesn't address the underlying problem. Remove the source of phosphates and remove the problem, but that may not be possible. Since I have no control over my water, my solutions have been either to plant hardy, fast-growing plants like cabomba and hornwort that outcompete cyanobacteria for nutrients, to let algae grow and let my African cichlids or other algae eating fish graze it, to reduce the photoperiod on my tanks, or some combination of the three. Once the bulk of the nutrients is used up, water changes only add enough to support what is growing, rather than promoting a blossom of cyanobacteria. I've not had an outbreak in well over a year now, running 50 tanks. 

Interestingly, cyanobacteria has been linked to the "zombie" alligators of Lake Griffin, Florida. Run off from muck farms increased phosphate levels in the lake, promoting cyanobacteria growth, which in turn out-competed higher plants and algae. Few fish eat the stuff, so most fish species declined in the lake. But gizzard shad do eat cyanobacteria. Shad produce high amounts of thiaminase, which breaks down thiamine (vitamin B1). As the shad become more populous and other species declined, the gators ate more shad. The unbalanced diet caused the gators to take in more thiaminase, which prevented the alligators from getting the proper amount of thiamine. The gators suffered brain damage due to malnutrition, causing lethargy and paralysis. And thats the recipe for "zombie" gators.

WYite


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## ua hua

Wyomingite said:


> High phosphates are the primary cause, but high nitrates also contribute. Cyanobacteria do not need much light.
> 
> I'm on well water in a subdivision built on old farmland. My water is occasionally high in phosphates and nitrates, and phosphate levels and subsequent cyanobacteria blooms seemed to come in conjunction with wet weather. Makes sense, since water drains into the aquifer, taking phosphates and nitrates accumulated in the ground from decades of farming with it. I had this problem with almost every tank for over a year initially, until either algae or plants became established. Needless to say, I'm a little less meticulous about algae than I used to be when I lived in town, especially in my non-planted, cichlid tanks.
> 
> Erythromycin will kill it, and is good for the occasional or one time outbreak. But since this a continouos problem in this tank, it doesn't address the underlying problem. Remove the source of phosphates and remove the problem, but that may not be possible. Since I have no control over my water, my solutions have been either to plant hardy, fast-growing plants like cabomba and hornwort that outcompete cyanobacteria for nutrients, to let algae grow and let my African cichlids or other algae eating fish graze it, to reduce the photoperiod on my tanks, or some combination of the three. Once the bulk of the nutrients is used up, water changes only add enough to support what is growing, rather than promoting a blossom of cyanobacteria. I've not had an outbreak in well over a year now, running 50 tanks.
> 
> Interestingly, cyanobacteria has been linked to the "zombie" alligators of Lake Griffin, Florida. Run off from muck farms increased phosphate levels in the lake, promoting cyanobacteria growth, which in turn out-competed higher plants and algae. Few fish eat the stuff, so most fish species declined in the lake. But gizzard shad do eat cyanobacteria. Shad produce high amounts of thiaminase, which breaks down thiamine (vitamin B1). As the shad become more populous and other species declined, the gators ate more shad. The unbalanced diet caused the gators to take in more thiaminase, which prevented the alligators from getting the proper amount of thiamine. The gators suffered brain damage due to malnutrition, causing lethargy and paralysis. And thats the recipe for "zombie" gators.
> 
> WYite


 
So the moral of the story is don't eat BGA or you will turn into a zombie.:hihi:


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## m00se

So I guess it begs the question: In tanks where phosphates are limited, where does the cynaobacteria get it's foothold? In tanks where folks aren't dosing PO4 it still appears..


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## plantbrain

Wyomingite said:


> High phosphates are the primary cause, but high nitrates also contribute. Cyanobacteria do not need much light.
> 
> WYite


Now let's mess with the high side:

I dose 30-45ppm of NO3 and 15 ppm of PO4 as KNO3 and KH2PO4 weekly to this tank, see any evidence of BGA? Any algae for that matter?










Tank also is dosed 2 ppm of Fe as a proxy for traces......as CMS +B.

If what you stated is true, then how come I do not have algae or BGA? 

If could be many many things(this we cannot ever be 100% certain).......but those 2(PO4 and NO3 being high) are not it(this we can be certain).

I think 15ppm and 30-45ppm a week of those would qualify for being on the "high" side.

Maybe I just got lucky this one time? I have about 50 tanks going back 20 years with similar results:


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## Kevchan

I think it's cause you have a ton of plants in there already?


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## Brian Mc

Great story, Wyomingite. I have been out of the game for a few years but low O2 levels always seem to have a hand in this.

That's not a problem in your tank, Tom. I want my Red Ludwigia! :icon_twis


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## Wyomingite

"Cell-bound and extracellular phosphatase activities of cyanobacterial isolates"; Microbial Ecology; Whitton, et al, 1991.

Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management; World Health Organization; edited by Chorus and Bartram, 1999.

The Biology of Cyanobacteria; University of California Press; edited by Carr and Whitton, 1982.

"Competition between picoplanktonic cyanobacteria and heterotrophic bacteria along crossed gradients of glucose and phosphate"; Microbial Ecology; Drakare, 2002.

Doesn't really matter whether ya believe me or not, Plantbrain. The literature tells the story. 

I'd hafta say ya don't have phosphates in excess of what yer plants are using. Yer plants are well-established and ya have enough light to keep growth at a pace that keeps algae and cyanobacteria blooms under control. If yer also dosing CO2, then the plants have enough carbon to use up the phosphates, leaving nothing or little left to promote a cyanobacteria bloom. 

Brian Mc, low O2 levels are a result of eutrophication induced by the cyanobacteria, rather than being a direct cause of the cyanobacteria bloom. Once cyanobacteria get a foothold, they outcompete other microrganisms and higher plants, killing them, releasing more nutrients in the water through decomposition. Decomposition uses up O2. In addition, the reduction in DO can release bound phosphates from organic and inorganic substances in contact with the water into the water column, creating an even larger pool of phosphates for the cyanobacteria to use. It's a self-perpetuating circle. Unlike algae and higher plants, cyanobacteria can photosynthesize in anoxic conditions, so low DO is irrelevant to their continued survival and prevents competition due to plants and algae reestablishing themselves. 

WYite


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## ua hua

Very interesting. Thanks for the info.


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## zergling

How high of phosphate levels do you need to induce cyanobacteria?

When I was derping around with dosing, I got to a point of dosing 20ppm of phosphates three times a week. That's 60ppm in a week, not including what is already existing in the water, and what is added with my heavy fish feeding. Not a single speck of cyanobacteria during that time.

Only time I got cyanobacteria was during the startup of my tank last year - this was when I seriously lacking on flow - just an old HOB filter and an old powerhead on a 65-ish gallon tank. Erythromycin, manual removal, and adding of flow (XP3 + 240gph koralia) resolved it the problem.

EDIT: I think I found the (partial) answer. 


> *Box 8.2 Thresholds for phosphorus control of different cyanobacterial ecostrategists*
> Knowledge of the prevalent ecotypes in a given water body leads to the following consequences for total phosphorus management:
> • If scum-forming ecostrategists prevail (such as Microcystis spp. or Anabaena spp.) cell numbers
> and biomass are likely to decline if total phosphorus concentrations can be brought well below 50
> μg I-1 P. This will also reduce scum formation, because less cells and colonies will be available to
> concentrate into scums. Nonetheless, some scums will probably continue to occur until
> phosphorus limitation becomes so severe that cell density (and therefore turbidity) decreases to
> the point where the depth of light penetration is as deep as the depth of large areas of the water
> body (Zeu = Zm). Under these conditions, vertical migration of these taxa is less effective because
> their buoyancy regulating mechanism requires some time in the dark (see section 2.2). Therefore,
> they lose their competitive advantage over other phytoplankton.
> • If dispersed ecostrategists prevail (such as the filamentous species Planktothrix agardhii,
> formerly named Oscillatoria agardhii) very pronounced "switches" may be expected. As
> phosphorus limitation reduces filament density, and thus turbidity, to the point where the
> relationship of the depth of light penetration to the depth of the mixed layer (Zeu/Zm) is greater
> than 0.4, these species are likely to disappear quite abruptly, and turbidity will increase even
> further, thus stabilising the result.
> • If metalimnetic ecostrategists prevail (such as Planktothrix rubescens), the water layer above
> these cells is usually quite clear. Very low concentrations of total phosphorus (often below 10 μg
> I-1 P) are necessary to decrease turbidity further and thus increase light intensity down to the
> depth inhabited by these species. If this can be achieved, metalimnetic ecotypes may disappear.
> If not, hydrophysical measures may be more successful in controlling their density.
> • If nitrogen fixing ecotypes prevail (such as Anabaena spp.), reduction of total phosphorus down
> to concentrations effectively limiting biomass will cause dissolved nitrogen concentrations in
> excess of uptake by phytoplankton. Nitrogen fixation is then no longer an advantage in
> competition over other cyanobacteria and algae. This may induce disappearance of the nitrogen
> fixing species.


It is talking about total phosphorous, and not phosphates, though. 


> The term total phosphorus is preferable to the term total phosphate, because results are reported
> in terms of phosphorus rather than phosphate. This is important because the weight of the PO4
> molecule is about three times that of its central P atom, and lack of specification in reporting
> results as to whether they refer to μg PO4 or μg P has caused considerable confusion in the
> literature.


Interesting tidbit on the 2002 article mentioned above:


> In treatments where *carbon limitation* slowed down the growth of heterotrophic bacteria, picophytoplankton became abundant and these organisms showed a positive response to P in combination with a negative response to glucose.



Hmmm, I wonder if low dissolved oxygen + phosphate = cyano proliferation? Meh, I'm sure it's not that simple....LOL! Low dissolved oxygen could easily be had if you have poor water movement, though!


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## maknwar

I'm thinking the only thing it could be is something in the aquasoil. My other tanks don't get cyno when over dosed or under dosed.


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## zergling

Also, I wonder if different species behave differently? I mean, spirulina is from two species of cyanobacteria....


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## willbldrco

I fought it for the better part of a year. I finally listened to Tom Barr's advice and performed a multi-pronged attack, details of which I captured in this post:

http://www.plantedtank.net/forums/algae/163761-algae-id.html#post1706838

Good luck with it. Once you have it, it's hard to get rid of!

Will


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## Canuck

> Because cyanobacterial blooms often develop in eutrophic lakes, it was originally
> assumed that they required high phosphorus and nitrogen concentrations. This
> assumption was maintained even though cyanobacterial blooms often occurred when
> concentrations of dissolved phosphate were lowest. Experimental data have shown that
> the affinity of many cyanobacteria for nitrogen or phosphorus is higher than for many
> other photosynthetic organisms. This means that they can out-compete other
> phytoplankton organisms under conditions of phosphorus or nitrogen limitation.


Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management; World Health Organization; edited by Chorus and Bartram, 1999. Section 2.2.4


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## Wyomingite

Good point, Canuck. However, it DOES NOT state that high phosphates DO NOT contribute to cyanobacteria blooms. It states that cyanobacteria in nutrient-deficient conditions will out-compete other organisms for available phosphorous, and no where have I stated that high phosphorous concentrations were required. There are any number of examples in the scientific literature that support my assertion that high phosphates in a body of water triggers cyanobacteria blooms, with run-off from agriculture being the primary cause. This is a world-wide problem.

Even in nutrient-deficient situations it is not as simple as saying “the cyanobacteria get all the available phosphorous”. There are too many other factors affecting uptake: photoperiod, pH, alkalinity, temperature, etc. 

The real failing in this as an argument to my point is that an aquarium is a closed system and nutrient-deficient aquariums are seldom the rule, no matter how hard we strive for that state. Food, metabolic wastes from fish, fertilizers, leaching from wood/rocks/ornaments, nutrients suspended/dissolved in water from water changes, and other factors all contribute to the nutrients in an aquarium. By nature, aquariums tend to be nutrient-rich environments. 

After 20+ years I’ve learned that applying my professional knowledge/experience to my hobby isn’t always a straight across affair. I hafta analyze what applies to the hobby and what does not. Anyways, methinks a pithy quote would have been premature.

The important thing for the aquarist in terms of cyanobacteria is the following:

"Phosphorous is the major nutrient controlling the occurence of water blooms of cyanobacteria in many regions of the world, although nitrogen compounds are sometimes relevant in determining the amount of cyanobacteria present. However, in contrast to planktonic algae, some cyanobacteria are able to escape nitrogen limitation by fixing atmospheric nitrogen.. The lack of nitrate or ammonia, therefore, favors the dominance of these species. Thus, the availability of nitrate or ammonia is an important factor in determining which species are present.” 

Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management; World Health Organization; edited by Chorus and Bartram, 1999. p. 6.

I realized several posts back I should have used "excess" rather than high, or “excess and /or high”. Regardless of wording, the end deduction is the same: phosphates must be available to promote cyanobacteria growth. If all the available phosphorous in the aquarium is not being used by plants or algae, the cyanobacteria has a foothold for growth. Limit the source of the phosphates and ya limit the cyanobacteria.

Cheers,

WYite


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## plantbrain

Wyomingite said:


> Doesn't really matter whether ya believe me or not, Plantbrain. The literature tells the story.


Poorly applied literature references tells a story, but does not support your claim. Was there shallow dense submersed vegetation in each study? No.......

Was this an aquarium? No........

Misapplied references do not offer support.

Particularly when we have many many aquariums where folks dose KNBO3 and KH2Po4 at 20ppm and 2 ppm respectively or higher, and have for many years(going on 2 decades now).

Those results falsify your claim.
There is not and, buts or maybes about it, it does not say WHY BGA forms, blooms, grows well etc........it merely states what cannot be the the cause independent of other factors.

For your claim/hypothesis to be correct, we'd have to see most folks getting BGA, but that is simply not the case. In natural systems lacking dense wetland plants, loading N and P can cause algae blooms. If you add fertilizer to a dense submersed plant lake, you get more weeds.



> I'd hafta say ya don't have phosphates in excess of what yer plants are using.


I have 3-7 ppm as PO4 at all times. Clearly quite non limiting to any and all BGA and any and all algae. This is NOT something new either, I've had high PO4 and have suggested folks to dose it since 1996 in articles. 



> Yer plants are well-established and ya have enough light to keep growth at a pace that keeps algae and cyanobacteria blooms under control. If yer also dosing CO2, then the plants have enough carbon to use up the phosphates, leaving nothing or little left to promote a cyanobacteria bloom.


Plants(macrophytes, this will include Chara and Nitella) are not competing with algae or BGA for nutrients. Light perhaps, but not CO2 or nutrients. The point where P becomes limiting is roughly 3ppb for most algae and BGA, for submersed plants, it's around 50ppb. This is over an order of maginitude.

CO2 is even a larger factor.

Plants do quite well if the focus and their needs are met, that is the goal here, not to limit or outwit algae/BGA.

Here is a much better study that supports what we see in aquariums:

http://lakewatch.ifas.ufl.edu/LWTEAMFOLDER/CanfieldPubs/macrophyte.pdf

These lakes actually have aquatic submersed plants in them.


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## plantbrain

willbldrco said:


> I fought it for the better part of a year. I finally listened to Tom Barr's advice and performed a multi-pronged attack, details of which I captured in this post:
> 
> http://www.plantedtank.net/forums/algae/163761-algae-id.html#post1706838
> 
> Good luck with it. Once you have it, it's hard to get rid of!
> 
> Will


Focused on the plants, good CO2 etc.
Not the algae.......
Algae can be annoying though.


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## plantbrain

Wyomingite said:


> Good point, Canuck. However, it DOES NOT state that high phosphates DO NOT contribute to cyanobacteria blooms. It states that cyanobacteria in nutrient-deficient conditions will out-compete other organisms for available phosphorous, and no where have I stated that high phosphorous concentrations were required. There are any number of examples in the scientific literature that support my assertion that high phosphates in a body of water triggers cyanobacteria blooms, with run-off from agriculture being the primary cause. This is a world-wide problem.


I agree that BGA will have a lower threshold of limitation for P and N than algae or plants. This makes biological sense. There are some larger BGA's and then some really small phytoplankton algae, so you might have some crossover if you went to extremes.

You have mentioned PO4 a lot, and say high amounts, but you have not stated once what those amounts are curiously.

I have.

I've shown one aquarium(I got plenty more where this came from) where I've dose 5ppm 3x a week of PO4, this is far beyond limiting concentrations/dosing for any plant or algae or BGA.

Here's another one of my tanks:










This tank has had this same dosing routine going on 6th year. 
No algae issues. I've had a tiny bit of BGA below the gravel on the glass every so often, but it's never been any issue.

So where is all my algae if what you state is true?
I'd like to know.

I think this hypothesis that limiting PO4 cures algae was lost in this hobby starting about 1995 and it was toast by 1997. 



> Even in nutrient-deficient situations it is not as simple as saying “the cyanobacteria get all the available phosphorous”. There are too many other factors affecting uptake: photoperiod, pH, alkalinity, temperature, etc.


So perhaps it has little to do with PO4 after all:tongue:
In other words, BGA/algae are not caused directly, independent of other factors, but say 1-5ppm of PO4 from KH2PO4 dosed 1-3x a week.



> The real failing in this as an argument to my point is that an aquarium is a closed system and nutrient-deficient aquariums are seldom the rule, no matter how hard we strive for that state.


I agree, so why fight it, embrace the plant's needs and focus on what makes them thrive, algae are rarely an issue if this is done. Why that is.....is another matter, but where plants grow well/best, they have ample ferts, ample CO2, ample light. If their growth suffers, then epiphytic algae can attack and cover the plants.

Healthy plants define the system where there's 30-50% coverage or more, not the nutrients. If there are no plants in the system, then these smaller algae and BGA will define the system.



> I realized several posts back I should have used "excess" rather than high, or “excess and /or high”. Regardless of wording, the end deduction is the same: phosphates must be available to promote cyanobacteria growth. If all the available phosphorous in the aquarium is not being used by plants or algae, the cyanobacteria has a foothold for growth. Limit the source of the phosphates and ya limit the cyanobacteria.
> 
> Cheers,
> 
> WYite


So why do my tanks after close to 20 years grow like mad, 300-400 species all thrive, grow as healthy if not more healthy than the best examples in the hobby?

This is not one or two tanks for a week or two, these are 50+ tanks, 1600 gallons down to 1 gallon, over decades time spans. 



















A good myth is hard to kill.


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## Wyomingite

Well, a little offended, Mr. Barr? Misapplied references do not offer support, eh? Well the reference you supplied isn't an aquarium either, and is just as misapplied then. My sources focused on the biology of cyanobacteria, which will be consistent in any environment. 

http://www.thetropicaltank.co.uk/algae.htm#blue-read the section on BGA.

http://www.who.int/water_sanitation_health/resourcesquality/toxcyanchap8.pdf - read the section about limiting cyanobacteria growth through phosphorous control, and the very first paragraph about competition with aquatic plants.

I'll quote this again:

"Phosphorous is the major nutrient controlling the occurence of water blooms of cyanobacteria in many regions of the world, although nitrogen compounds are sometimes relevant in determining the amount of cyanobacteria present. However, in contrast to planktonic algae, some cyanobacteria are able to escape nitrogen limitation by fixing atmospheric nitrogen.. The lack of nitrate or ammonia, therefore, favors the dominance of these species. Thus, the availability of nitrate or ammonia is an important factor in determining which species are present.” 

Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management; World Health Organization; edited by Chorus and Bartram, 1999. p. 6.

Bottom line is cyanobacteria are phosphorous dependent. Period. No one is yet to dispute that. This is not a hypothesis, nor a theory. This is clearly stated in the literature, in more than one source. Quote your source stating cyanobacteria aren't phosphorous dependent or drop it. Seriously.

The presence of excess phosphorous doesn't guarantee that a cyanobacteria bloom will occur, I never stated that. But cyanobacteria blooms do occur when there is excess phosphorous. Disprove that. That it hasn't happened in your tank does not prove that excess phosphates and excess nitrates are not the cause of cyanobacteria blooms. Thats like saying that I drive above the speed limit and haven't had an accident, so no one who drives above the speed limit can have an accident. Your references to overdosing do not falsify my "claim". And please quote your source that BGA does not compete with plants for nutrients. Anytime two species utilize the same resource, they compete (also see above link.) 

The problem stated by the OP was continual cyanobacteria blooms. I didn't offer speculation that it could be low O2 or some other cause. I offered actual conditions that are conducive to cyanobacteria blooms and suggested remediation. What was your reply? Something along the lines of we can't be sure what causes that.

I'm done with this topic. I've obviously upset the apple cart and offended the "in-crowd" and it seems some people aren't willing to keep an open-mind or willing to accept somebody else may have something different to contribute.

Cheers,

WYite


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## ua hua

Wyomingite said:


> Well, a little offended, Mr. Barr? Misapplied references do not offer support, eh? Well the reference you supplied isn't an aquarium either, and is just as misapplied then. My sources focused on the biology of cyanobacteria, which will be consistent in any environment.
> 
> http://www.thetropicaltank.co.uk/algae.htm#blue-read the section on BGA.
> 
> http://www.who.int/water_sanitation_health/resourcesquality/toxcyanchap8.pdf - read the section about limiting cyanobacteria growth through phosphorous control, and the very first paragraph about competition with aquatic plants.
> 
> I'll quote this again:
> 
> "Phosphorous is the major nutrient controlling the occurence of water blooms of cyanobacteria in many regions of the world, although nitrogen compounds are sometimes relevant in determining the amount of cyanobacteria present. However, in contrast to planktonic algae, some cyanobacteria are able to escape nitrogen limitation by fixing atmospheric nitrogen.. The lack of nitrate or ammonia, therefore, favors the dominance of these species. Thus, the availability of nitrate or ammonia is an important factor in determining which species are present.”
> 
> Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management; World Health Organization; edited by Chorus and Bartram, 1999. p. 6.
> 
> Bottom line is cyanobacteria are phosphorous dependent. Period. No one is yet to dispute that. This is not a hypothesis, nor a theory. This is clearly stated in the literature, in more than one source. Quote your source stating cyanobacteria aren't phosphorous dependent or drop it. Seriously.
> 
> The presence of excess phosphorous doesn't guarantee that a cyanobacteria bloom will occur, I never stated that. But cyanobacteria blooms do occur when there is excess phosphorous. Disprove that. That it hasn't happened in your tank does not prove that excess phosphates and excess nitrates are not the cause of cyanobacteria blooms. Thats like saying that I drive above the speed limit and haven't had an accident, so no one who drives above the speed limit can have an accident. Your references to overdosing do not falsify my "claim". And please quote your source that BGA does not compete with plants for nutrients. Anytime two species utilize the same resource, they compete (also see above link.)
> 
> The problem stated by the OP was continual cyanobacteria blooms. I didn't offer speculation that it could be low O2 or some other cause. I offered actual conditions that are conducive to cyanobacteria blooms and suggested remediation. What was your reply? Something along the lines of we can't be sure what causes that.
> 
> I'm done with this topic. I've obviously upset the apple cart and offended the "in-crowd" and it seems some people aren't willing to keep an open-mind or willing to accept somebody else may have something different to contribute.
> 
> Cheers,
> 
> WYite


 
I think this hobby and this site needs people like you to contribute your experience and not shy away when others may not agree with what you say. This hobby is far from being completely understood and is ever evolving. There is nothing wrong with questioning the majority. Tom of all people should know this as I'm sure what he was trying to prove with his EI dosing was going against the mainstream when it was first introduced. Everyone needs to contribute their experiences good and bad and make this a hobby that shares information which each other. I have had experiences with BGA and never quite figured out what the cause of it was as everyone always says the same thing about low N and not enough flow. Is the low N the cause of the BGA appearing or is the low N that is present in the system because the cynaobacteria has used up all the N thus resulting in low N?


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## youjettisonme

> Bottom line is cyanobacteria are phosphorous dependent. Period. No one is yet to dispute that. This is not a hypothesis, nor a theory. This is clearly stated in the literature, in more than one source. Quote your source stating cyanobacteria aren't phosphorous dependent or drop it. Seriously.
> 
> The presence of excess phosphorous doesn't guarantee that a cyanobacteria bloom will occur, I never stated that. But cyanobacteria blooms do occur when there is excess phosphorous. Disprove that.


This is my tank right now. The substrate is Akadama Double-Red. I have zero ppm of phosphate. I dose nothing right now except for a very minimal amount of N and K. I am currently experiencing a cyano outbreak that's on just about everything. So, it is absolutely possible for cyano to thrive without the presence of phosphates. 

Now... how to actually get rid of it in my tank. The problem is that I can't just load up on nutrients to make the plants happy because the TDS will shoot up higher than it needs to be in a PRL tank. 

Anyone with any ideas?


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## plantbrain

Most of those plants are lower light, so you can reduce the light and thus the nutrient demand and dose, but dose light, but not for the algae/BGA, rather, for the plants.


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## plantbrain

In research, you MUST HAVE aquatic plants present to suggest nutrients and algae blooms within planted aquariums. Not doing so.... skews the research and does not support your contention. Many studies suggest N and P induce algae blooms, but such systems lack submersed aquatic plants at 30-100% coverage. You need around 30% or more to have the plants define the system from the top down, not bottom up control like with nutrients.



Wyomingite said:


> Bottom line is cyanobacteria are phosphorous dependent. Period. No one is yet to dispute that.


Well of course. That is why it is called an essential element. Why is this even stated? 

I stated that higher concentrations of PO4(eg non limiting to both plants and any algae/BGA) do NOT induce BGA in aquariums, if they did, everyone that doses EI would have a lot of BGA, but that is not the observation or the case.

This is independent of any other factors.

So higher levels of PO4 do not induce BGA/algae. You cannot get around this specific planted tank observation. Where there are a high % surface coverage of plants, there is no correlation between nutrients and algae.

I suggest a good read: Bachmann 2002.
http://lakewatch.ifas.ufl.edu/LWTEAMFOLDER/CanfieldPubs/macrophyte.pdf

What is a limiting range for BGA?
What is the specific species that infest our tanks?
Oscillatoria: 
http://133.25.19.145/pdb/images/Prokaryotes/Oscillatoriaceae/Oscillatoria/index.html

This is about the only genus we have issues with.
So the rest of those species are not particularly specific to aquarium.

The South Florida water management district has a periphyton group, they study BGA crust in the Everglades. Shallow well planted regions. To restore the Everglades back to it's functional state, they need roughly under 10 ppb BILLION, ideally around 3-10ppb or so as I recall. Submersed plants around 50ppb, so you will limit and hurt plants long before you limit BGA via dosing.
It's like trying starve the mice while also feeding elephants at the same time at the same troft.



> This is not a hypothesis, nor a theory. This is clearly stated in the literature, in more than one source. Quote your source stating cyanobacteria aren't phosphorous dependent or drop it. Seriously.


Here's the disconnect: Equate non limiting values with a required essential element. No one is debating whether P is an essential element. Where did this come from? I never once brought that up.

I simply have siad that at higher concentrations, in the 1-10 ppm range for PO4, 2-3 orders of magnitude higher than the limiting range, that BGA is a non issue due independently from dosing KH2PO4 and KNO3.

You are suggesting that there is dependency.

Above 10-20 ppb, they are independent, it's only when you get well below the limiting values for plants, can you start to limit BGA with P. Few test kits even have decent accuracy and measurement this low, it can be done, but error values of 3ppb and a range of 10ppb or under are extremely tough for the periphyton group, I think aquarist will have a tough time. 



> The presence of excess phosphorous doesn't guarantee that a cyanobacteria bloom will occur, I never stated that.


You suggested it does. Now you want this both ways? 



> But cyanobacteria blooms do occur when there is excess phosphorous.


Right there.



> Disprove that. That it hasn't happened in your tank does not prove that excess phosphates and excess nitrates are not the cause of cyanobacteria blooms.


Actually it does. Here's the rub: *INDEPENDENT *of other factors. You do not get to say it is independent and dependent, it is on eor the other, it cannot be both for the same system. 
If you have dependency on other factors, of which there may be many, then why even worry about N or P being at a higher level? Non limiting is non limiting regardless.
That's why they use non limiting nutrients to study other factors like light and CO2 for plant growth. It's no longer dependent when you dose that way. 
Or if they want to study say just P, they provide all other factors at non limiting nutrient values, thus only P is the dependent variable. The experiment typically has an upper bound(eg non limiting) and a lower bound(DI water etc, no ferts) and then a range of concentrations in between. 
Adding more will not induce BGA. If there was dependency independent of the other factors, we would HAVE to have a high % of aquarist who dose KH2PO4 and KNO3 at say 5ppm PO4 and 15-20ppm a week have BGA, that is simply not the case. This clearly demonstrates that adding "excess" PO4 or NO3 does not induce algae or BGA. It's repeatable and has been for about 15 years now in the hobby.

This is not a new thing.



> Anytime two species utilize the same resource, they compete (also see above link.)


Not if they occupy a very different niche both spatially, temporally and in size. I guess mice and elephants cannot coexist since they are both herbivores eh? Light is about the only thing algae and plants really compete for and this is even much more reduced for the genus that pesters us. 

Until you get insanely low values, you are not going to have any competitions and if you do, it'll be the plants that die/stop growing long before the BGA.



> The problem stated by the OP was continual cyanobacteria blooms. I didn't offer speculation that it could be low O2 or some other cause. I offered actual conditions that are conducive to cyanobacteria blooms and suggested remediation. What was your reply? Something along the lines of we can't be sure what causes that.


I can only be sure of what I can falsify, we can never be 100% certain of cause and aquariums in the little glass box is a very different issue than a lake, or a stream, or the middle of a gyre in the Pacific. We deal with one genus(maybe a couple more, but they are rare) of BGA and controlling it is fairly straight forward.

Mostly through growing plants, not trying to outwit algae.

Paul Sears and Kevin Conlin long ago proposed this:

http://www.thekrib.com/Plants/Fertilizer/sears-conlin.html

It's just a hypothesis, so I dosed more and waited for algae, instead, I had awesome plant growth and no algae.

Conclusion, the hypothesis must be false(this next part is important)... independent of other factors. It does not say that removing all essential elements is not dependency

Paul even made the statement we need some PO4...and that 0.00ppm is bad and will limit plant growth as well. What I showed was that it need not be in this tight narrow range say +/- 0.1 ppm and a target of 0.2ppm.

I have had high PO4 for the last 15 years and I have many many examples of some nice planted scapes and plant growth, so have many others. 

Research is a good place to start, but it does not imply that the same principles work in aquariums. There needs some corroboration in what we see in the field and aquarium. Bachmann's study does that. In a lake without much plant growth % cover, I agree adding ferts will likely increase algae total concentrations and diversity. The key is % plant coverage. Same in our tanks and even in the pond hobby. If you have say 30-50% or more coverage, you likely will have a plant defined system.
Why this is I can only speculate. I do not know much, but I do know that adding a specific non limiting range of nutrients does not induce any algae.

Final note, do not take things personally. This is a discussion about plants, stick to that.


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## KH2PO4

youjettisonme said:


> This is my tank right now. The substrate is Akadama Double-Red. I have zero ppm of phosphate. I dose nothing right now except for a very minimal amount of N and K. I am currently experiencing a cyano outbreak that's on just about everything. So, it is absolutely possible for cyano to thrive without the presence of phosphates.
> 
> Now... how to actually get rid of it in my tank. The problem is that I can't just load up on nutrients to make the plants happy because the TDS will shoot up higher than it needs to be in a PRL tank.
> 
> Anyone with any ideas?


What's your test kit? Some, such as API's, can detect only orthophosphate 
(inorganic phosphate). Cyanobacteria can use organic phosphate.

Just when you type "Cyanobacteria organic" in Google. 
The word "phosphorus" will follow automatically...

IME, I've found stopping adding KH2PO4 "helps". But I've to control also 
organic matter to get rid of it. When I resumed KH2PO4, it came back again.

I think we're dealing with multifactorial problem. That's why adding 
high load of PO4 doesn't create problem for some, including me in the past.


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## KH2PO4

Cyanobacteria can enslave other algae to get phosphate.
http://www.youtube.com/watch?v=TkeI0LntI9w


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## fish878

*cynobacteria decrease*

I've had a problem with cynobacteria in my dwarf hair grass (feels funny saying that). It is really difficult to remove from this plant. However, using the multi-pronged approach suggested earlier in this thread (origins point to Tom Barr) and very maticulous manual removal, I have had a severe decrease in cyno over the last week. I think purchasing another filter for added flow really stopped the spread of it while the other actions have decreased it. For manual removal I shake the plant which detaches the cyno and use my water syphon to suck it up. I originally was using hydrogen peroxide but it harmed the grass so now I'm just using excel. I dose using the EI method and have not decreased my ferts during this time period. I've attached a crummy picture of how the cynobacteria looks in the dwarf hair grass.


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## BruceF

I think one can claim that high light, co2 injection, ei dosing, high flow sumps and 50% water changes once a week prevent cyanobacteria. I am just not sure you can claim that therefore cyanobacteria is not effected by phosphate levels or any other variable you would like to isolate.


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## mistergreen

I think it's more correct to ask, "What environment causes BGA to reproduce rapidly?"


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## HD Blazingwolf

for a simpler viewpoint

i'll point out that a test kit with 0 on phosphates can still support cyano bacteria growth because it can survive off of very low levels of po4

I've never had a tank or helped someone with a tank that had cyano as a result of proper biofiltration. THIS INCLUDED but is not limited to, decent flow, good oxygenation fo the water which is the most important, and a well established bacterial colony. Planted tank or not

low nitrates exacerbate the issue
low flow exacerbate the issue
cyano grows independent of kh and tds.. Ph hasn't seemed to matter either

these are just a kids opinions and viewpoints. but seen time and time again. and never seen in personal tanks that have above and beyond flow through the filtering system(10X turnover) which is comprised of 5% mechanical and 95% biological.

hope this helps


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## Snowflake311

I had this blue green algea so bad I almost gave up on the tank. I was ready to just sell the whole tank I was so mad at it. 

I was so fed up with it I took everything out of the tank. I had sand substrate I removed it all added a plant substrate. Re planted the tank but there were still bits of BG algea left in the tank. I raised the light up 4" From the water surface. 

Cleaning the filter was and is key to getting rid of this stuff. It thrives in a dirty tank that has low o2 with high light. 

I now keep the filter clean and my water flow is nice and strong. Allowing for good flow around the tank. I also have more surface agitation and added more plants. Since doing this I have never seen a spot of BGA. Or any other algea yet I added rams horn snails to the tank and they keep it spot less. 

How often do you clean your filter?


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## kalawai2000

I had cyano growing all over my 12 gal tank..it took months to get rid of it. I was using the correct antibiotics for it. I was so sick and tired of fighting it that I tore the whole tank down and started over, I only had a few fish in the tank. I transferred them to the pond/barrel and did the change to the tank. After about one week the cyano died off and now this tank is doing great. I did add new plants and replaced the lighting to LEDs. I'm not sure which change made the cyano go away.


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