# Algae, Cyanobacteria and Plants - An Hypothesis?



## jaypeecee (18 Oct 2021)

Hi Everyone,

Based on a lot of observations and measurements, I'd like to put forward a suggestion/hypothesis. It is this:

Perhaps cyanobacteria (BGA) and algae need _inorganic_ phosphate (orthophosphate)/PO4--- in order to grow and survive. But higher plants (macrophytes) can use either _inorganic_ phosphate or _organic_ phosphate as their source of phosphorus?

Tomorrow, I'll explain my rationale for this suggestion when I, hopefully, have rather more time. In the meantime, any initial comments would be appreciated.

JPC


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## MichaelJ (19 Oct 2021)

Hi @jaypeecee  Good to see you back on the forum!   Noticed you've been off for a while.

I cant say much about BGA as I don't have any and haven't had any for a very long time - always associated BGA with _immature_ tanks - pretty vague I know...  look forward to hear your rationale here.

Cheers,
Michael


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## jaypeecee (19 Oct 2021)

Hi again...

OK, I'm already starting to see things differently. In one of my tanks, I have been closely monitoring the growth of a collection of Java Ferns. KH was maintained at 2.0 - 2.5 dKH and pH was 6.7 - 7.0, corresponding to a CO2 concentration of around 10 ppm. CO2 was running 24/7. Inorganic phosphate (orthophosphate/PO4---) had been showing less than 0.02 ppm* for three weeks. The small amount of cyanobacteria that had been present dwindled as time progressed. In the meantime, the Java Ferns were flourishing putting out new leaves every few days. And they were healthy leaves. How could this be? That's when I started to think that the Java Ferns were able to use a different source of phosphorus other than inorganic phosphate. Perhaps there was organic phosphorus in the tank water? Unfortunately, I was unable to test for that.

Now, I'm beginning to think that the Java Ferns were using _stored phosphorus_ from what I understand to be known as luxury uptake of nutrients.

I suggest also reading the following as it is pertinent to my meanderings above (and note the date of the article below):



			PMDD :: aquarium fertilizer :: articles :: PMDD original text: Control of Algae in Planted Aquaria
		


* JBL PO4--- Test Kit

JPC


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## Zeus. (19 Oct 2021)

jaypeecee said:


> PMDD :: aquarium fertilizer :: articles :: PMDD original text: Control of Algae in Planted Aquaria



Great Find , and interesting read/theory. I will be watching thread with interest and looking forward to more feedback esp from @dw1305 and @ceg4048


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## dw1305 (19 Oct 2021)

Hi all, 


jaypeecee said:


> Now, I'm beginning to think that the Java Ferns were using _stored phosphorus_ from what I understand to be known as luxury uptake of nutrients.


That would be my guess. Phosphate is <"highly mobile within the plant">.


jaypeecee said:


> were able to use a different source of phosphorus other than inorganic phosphate. Perhaps there was organic phosphorus in the tank water?


Polyphosphate has been <"used as fertiliser">, but I know no more.

cheers Darrel


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## ceg4048 (19 Oct 2021)

Zeus. said:


> Great Find , and interesting read/theory. I will be watching thread with interest and looking forward to more feedback esp from @dw1305 and @ceg4048


Karl,
       These are excerpts from  messages from the venerable website The Krib 
 A lot of the data is from the experiments of Paul Sears and Kevin Conlin. These guys were great and they brought us the original Poor Man's Dosing Drops (the first D in PMDD actually is the first letter in a famous company's dosing drops but the acronym was changed to avoid litigation). In any case Sears and Conlin did not go far enough because at that time (20 years ago) there had not yet been any correlation made between filamentous algae and CO2, AND both of these guys suffered from a mind set against PO4. That is why they developed PMDD to be devoid of PO4 and is a failure unless the hobbyist's water source is high in PO4. It was later rectified by others to be "PMDD+PO4", which is very similar to EI. 
In many of their case studies CO2 related algae appeared, which they did not recognize as being CO2 related and they attributed the appearance of the algae to what we now know to be unrelated causal factors, such as Fe and so forth.
ALL filamentous algae and Red algae is caused by poor CO2. They were unaware of that 20 years ago. Folks were using DIY yeast CO2 and so suffered greatly with algae, clueless of the cause.

Any organic nutrient source is essentially trapped within the molecular structure of organic objects, such as feces, uneaten food, detritus and plant matter. These are only released in the water when bacteria have broken down the material to get at the nutrient. So using organic nutrient sources is a very bad idea because the environment has to degrade in order for the nutrient to be made available. Plants do not typically uptake organic molecules. The uptake and metabolic pathways are typically selective and specific to the nutrient molecule of interest. That means there is a special NO3 channel, a special PO4 channel, and so forth. The PO4, or NO3, or NH4 ion must not be hidden or embedded within another molecule. The plant would interpret that molecule to be pollution. Inside the plant, however is a different story. Nutrient ions that are toxic are chelated using organic molecules to shield the plant from toxicity and are then delivered to the site where they are released and used in whatever chemical reaction is required of that ion. All the micronutrients are actually highly toxic metal ions. NH3 is toxic as hell, so it is chelated and then broken down into amino acids or their precursors as quickly as possible. NO3 and PO4 are non-toxic and can easily be stored without the need for chelation.

So one must be very careful using historical data that has long since been disqualified. Twenty years from now we will understand things that we do not yet understand now. If we continue to draw conclusions based on this type of data, not recognizing their origin, relevance or context, then we are doomed to repeat the very same failures. 

Cheers,


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## jaypeecee (19 Oct 2021)

Hi @ceg4048 

Thanks for your input.

I'll reply in more detail - hopefully, tomorrow. It's late here in Old Blighty.

JPC


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## John q (20 Oct 2021)

Hey @jaypeecee 

I actually admire the fact that you are willing to test your suspicions, most folk don't and simply take things as read. I do agree with Clive that one should be careful about drawing definitive conclusions from one specific result though.

It will be interesting to see how the ferns fair in the long term once their nutrient stores are depleted, it would also be interesting to see at some point in the future what effect the addition of P04 makes to this experiment.


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## dw1305 (20 Oct 2021)

Hi all,


John q said:


> It will be interesting to see how the ferns fair in the long term once their nutrient stores are depleted, it would also be interesting to see at some point in the future what effect the addition of P04 makes to this experiment.


You could potentially run your tank phosphate (PO4---) depleted and <"I may already do this unintentionally">.

It would be fairly easy because

PO4---- <"is easy to remove"> from the water column,
PO4--- is <"relatively"> straightforward to <"test for"> using <"colorimetric methods">
PO4--- is <"highly mobile"> within the plant.
This would mean that if you decided your plants were phosphorus (P) deficient an addition of PO4--- ions (via KHPO4 etc) would lead to a very rapid growth response, because the plant can transport the phosphorus to the new leaf tissue etc.

The main issues would be:

Recognising that restricted plant growth was caused by P being <"Liebig's limiting nutrient">.
Accuracy of measurement of PO4---
I've never kept a high tech tank. or aimed for optimal growth rate, but the success of many EI users would suggest that there is more to it than just the <"level of PO4--- ions"> in the water column.

cheers Darrel


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## X3NiTH (20 Oct 2021)

Fell into a rabbit hole, went down fairly deep, I’m back up now and this is where I went!

When levels of available Orthophosphate are low there is an increase of Phytic Acid production within the plant, when the levels of orthophosphate increase there is a drop in phytic acid production. Phytic acid is a large molecule that has a caged structure that has a high affinity for filling that cage with a metal ion thus chelatory abilities.






This is a complex Organic Phosphate molecule and it is specialised for life mechanisms to release these bonds to get at the Phosphate, it can be achieved but it requires a Phytase to accomplish this, the Phytase is an Enzyme.



It is produced by some but not all organisms, particularly absent in non-ruminant animal species including fish (there’s some outliers). The specific Phytases required to reduce Phytates are called β-Propellor Phytases.





Here’s the β-Propellor Phytase tree of life.





Plant produced Phytases are represented only by the groups PAPhy and HAPhy, with the predominant variety in use being PAPhy (160 against 31). The others are produced by mychoriza, yeasts, phages and bacteria (including cyanobacteria which has a foot planted in two realms). 

The suggestion is that increased eutrophic conditions allow the above non plant actors in these systems to take greater advantage of any phytate present in the water column which is unavailable for plant uptake and reduce it back to orthophosphate, they have a competitive advantage over plants when it comes to doing this.


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## MichaelJ (20 Oct 2021)

X3NiTH said:


> Fell into a rabbit hole, went down fairly deep, I’m back up now and this is where I went!


Hi @X3NiTH Your chemistry knowledge and posts, as always, are very educational, but this one I feel like I would have to study up for a couple of months at least to understand. Is there a conclusion / hypothesis in there vs Cyano?


dw1305 said:


> You could potentially run your tank phosphate (PO4---) depleted


Hi @dw1305 What exactly does it mean to run the tank PO4 depleted?  Does it mean that there are no PO4 available in the water column - as in if you test for PO4 you get a zero reading and your essentially relying on the phosphate coming from organics (livestock/plant waste) as opposed to dosing?

Ok, I am just trying to ask some questions that may also help others that, like me, are bio-chemistry challenged, but wish to learn more 

I do not have enough knowledge to contribute to this, but I will say that high consistent weekly dosing of PO4 (currently dosing 10ppm PO4 with KH2PO4 down from about 20ppm/wk) in both my tanks have not caused any problems whatsoever - on the contrary it has helped eradicating GSA and probably other algae as well, of course all in combination with dosing other ferts in abundance, low light intensity, good flow and overall better maintenance.  

Cheers,
Michael


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## dw1305 (20 Oct 2021)

Hi all,


MichaelJ said:


> Is there a conclusion / hypothesis in there vs Cyano?


There is, it is this bit:


X3NiTH said:


> Plant produced Phytases are represented only by the groups PAPhy and HAPhy, with the predominant variety in use being PAPhy (160 against 31). The others are produced by mychoriza, yeasts, phages and bacteria (including cyanobacteria which has a foot planted in two realms).


The phytases are enzymes required to break down the phytic acid containing the PO4--- and all though there are a range of these, only two of them are found in green plants.


X3NiTH said:


> The suggestion is that ............ (non-plants) can take advantage of any phytate present in the water column which is unavailable for plant uptake and reduce it back to orthophosphate, they have a competitive advantage over plants when it comes to doing this.


Certainly plausible.


MichaelJ said:


> What exactly does it mean to run the tank PO4 depleted?


In my case <"all the nutrients are depleted">, I don't ever know which is Liebig's limiting one, but it is most likely to be <"nitrogen (N), potassium (K)"> and or <"magnesium (Mg) or iron (Fe)">


MichaelJ said:


> Does it mean that there are no PO4 available in the water column - as in if you test for PO4 you get a zero reading and your essentially relying on the phosphate coming from organics (livestock/plant waste) as opposed to dosing?


I don't actually know, because I don't regularly measure the PO4--- level, but I'd guess the plants are grabbing the phosphate ions when they are available and then <"shuffling them around the plant after that">.

cheers Darrel


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## jaypeecee (20 Oct 2021)

John q said:


> I actually admire the fact that you are willing to test your suspicions, most folk don't and simply take things as read. I do agree with Clive that one should be careful about drawing definitive conclusions from one specific result though.


Hi @John q 

My background is in the physical sciences so I try to understand to the best of my ability what my eyes are seeing - if it interests me sufficiently! It is certainly true that no cast-iron conclusions can be drawn from one set of data - empirical or otherwise. If my observations stimulate discussion and, even better, encourage others to repeat a similar experiment, then that makes it all worthwhile.

JPC


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## X3NiTH (20 Oct 2021)

MichaelJ said:


> Hi @X3NiTH Your chemistry knowledge and posts, as always, are very educational, but this one I feel like I would have to study up for a couple of months at least to understand. Is there a conclusion / hypothesis in there vs Cyano?



Yes this is deep into the realms of Organic Chemistry and my grasp of this is less than tenuous at best, the days reading began with an observation I see with Cyanobacteria. It began with basic chemistry and how Cyano prefers to assimilate Ammonia/Ammonium first and when these levels are tending toward zero it starts on Nitrate. In order to grow tissue quite obviously phosphate is going to be required and if a system is run with very little additional orthophosphate or tending to zero then you are only left with organic sources. It’s when you start to look at the differences between the Inorganic forms of Phosphate and the Organic forms in the water column and the fact that plants only uptake orthophosphate that there’s more to the rabbit hole.





Looking into this further in relation to nutrients in aqueous solution I was wholly dissatisfied with this statement on Organic Phosphate -





There is nothing minor about Phytic Acid, a plant produced chelate able to cage a metal ion (I’m going to point my finger at Iron) it’s exceptionally stable and environmentally persistent. Phytate can end up in the water column as a byproduct of tissue loss and destruction, plants can’t directly utilise this Phytate it requires a biological intermediary to disassemble the molecule to make the phosphate available, if Cyanobacteria can utilise this water column Phytate directly as a source of phosphate then how would it do this, cue the Phytases. 

This is the advantage Cyano has over plants with its exceptional ability to directly scavenge and utilise sources of Organic Phosphate and the metal ions contained within with no intermediary required to do so. I have a feeling that Iron is the main metal ion that is being targeted for.


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## jaypeecee (20 Oct 2021)

John q said:


> It will be interesting to see how the ferns fair in the long term once their nutrient stores are depleted, it would also be interesting to see at some point in the future what effect the addition of P04 makes to this experiment.


Hi again, @John q 

I have made a note of your comments and hope to report back on this.

JPC


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## X3NiTH (20 Oct 2021)

I forgot to add that Phytate is abundant in Fish Food! If you have lots of fish then there will be lots of Phytate and depending on how good or bad nitrification processes in your filtering system is there could be abundant Ammonia/Ammonium.


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## John q (20 Oct 2021)

MichaelJ said:


> Is there a conclusion / hypothesis in there






Sorry @MichaelJ  couldn't resist.


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## X3NiTH (20 Oct 2021)




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## MichaelJ (20 Oct 2021)

John q said:


> View attachment 175766
> Sorry @MichaelJ  couldn't resist.


You!! haha! love it!


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## jaypeecee (20 Oct 2021)

X3NiTH said:


> I forgot to add that Phytate is abundant in Fish Food!


Hi @X3NiTH 

Indeed, phytate is everywhere - well, not literally! Take a look at this:






						Phytate - an overview | ScienceDirect Topics
					






					www.sciencedirect.com
				




I've long been concerned about the amount of phosphate in fish food - particularly the processed foods. A good few years ago, the big names in fishkeeping were making a big thing about their low phosphate fish foods.

JPC


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## MichaelJ (20 Oct 2021)

X3NiTH said:


> View attachment 175768


Hey careful man! There is a serious science discussing here! 


Thanks @dw1305 and @X3NiTH for elaborating on the details. Very helpful.


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## jaypeecee (20 Oct 2021)

Hi Everyone,

I forgot to include the following:



			https://pdfs.semanticscholar.org/e776/c4ffe6882cb5003d08f868aac98be099afbb.pdf
		


It's only necessary to read the Abstract and Introduction to gather the stuff that's likely to be of interest to we aquarists.

JPC


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## jaypeecee (20 Oct 2021)

Hi @MichaelJ



MichaelJ said:


> Is there a conclusion / hypothesis in there vs Cyano?





jaypeecee said:


> Perhaps there was organic phosphorus in the tank water? Unfortunately, I was unable to test for that.



There would almost certainly be organics of some form in the tank water. Specifically, I was/am interested in knowing the Total Phosphate (orthophosphate + polyphosphate + organic phosphorus) content of my tank water. And I know of a laboratory that can run this test for a reasonable price. I know that inorganic phosphate (orthophosphate) was less than 0.02 ppm as I had no reason not to trust the JBL Test Kit. And, if there are any organic phosphorus compounds in my tank water, then it is/was not sufficient to sustain growth of cyanobacteria. Only the Java Ferns flourished.

At this point, I need a break as my 68 year old brain is starting to complain!

JPC


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## jaypeecee (21 Oct 2021)

jaypeecee said:


> There would almost certainly be organics of some form in the tank water.


Hi Everyone,

I should have added that, as I was growing Java Ferns, there was no substrate in my test tank. And no livestock of any description - that was visible to the human eye!

JPC


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## MichaelJ (21 Oct 2021)

jaypeecee said:


> Hi @MichaelJ
> 
> 
> 
> ...


Putting it in layman's terms, I suppose it's fair to boil it down to the origin of the Phosphate (and possibly Nitrate).    Is it organic, like the case is, if it originates from waste/decay, it promotes algae. Is it inorganic, like what we mostly dose, it will not cause algae by itself. It's all about what compound the Phosphate, or Nitrate for that matter, is part of. I.e. if it's bonded to Carbon(?) I know I am glossing over a lot of finer points here. Just trying to understand 

Cheers,
Michael


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## azawaza (23 Oct 2021)

I’m being nit picky (apologies) but it’s ‘a hypothesis’; ‘an hour’: due to the silent ‘h’, as how some would pronounce ‘herbs’, hence the article ‘an’ is used.


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## MichaelJ (23 Oct 2021)

azawaza said:


> I’m being nit picky (apologies) but it’s ‘a hypothesis’; ‘an hour’: due to the silent ‘h’, as how some would pronounce ‘herbs’, hence the article ‘an’ is used.


Game on!  You use *an* before a word beginning with a syllabic speech sound (not letter) - It does not matter how the word is spelled. It only matters how it is pronounced. So in this case it's '*a* hypothesis', as correctly noted.


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## jaypeecee (25 Oct 2021)

Hi Everyone,

Thanks for the excellent feedback to which I will return at a later date. In the meantime, an update...

Some of the Java Ferns are now, not surprisingly, starting to show nutrient deficiency. See the attached photo. Can anyone suggest which nutrient(s) is/are likely to be causing the browning of the leaves? If I can identify this/these nutrient(s), then I can possibly start to re-introduce it/them and monitor for changes not only to the Java Ferns but to the growth of Cyanobacteria.

Thanks in advance.

JPC


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## jaypeecee (25 Oct 2021)

azawaza said:


> I’m being nit picky (apologies) but it’s ‘a hypothesis’; ‘an hour’: due to the silent ‘h’, as how some would pronounce ‘herbs’, hence the article ‘an’ is used.


Hi @azawaza

It's not as straightforward as you have suggested. Please take a look at the following:









						A/an hypothesis?
					

Is it a or an hypothesis? I am not a native speaker (and not very language talented) so I would appreciate any explanation/rules.




					english.stackexchange.com
				




But, now, let's get back to the _topic_ of this thread - please.

JPC


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## MichaelJ (25 Oct 2021)

jaypeecee said:


> Can anyone suggest which nutrient(s) is/are likely to be causing the browning of the leaves?


Hi @jaypeecee  I would like to know the answer to that as well. Unfortunately, the specifics of what nutrients causes browning, as with so many other signs of deficiency, seems to be all over the place (Mg, Mn, K, Fe, P etc.)... besides obvious CO2 vs. light imbalance (which is probably not the case here)... It would be a big step forward if we could actually tell.
Cheers,
Michael


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## Hufsa (25 Oct 2021)

jaypeecee said:


> Can anyone suggest which nutrient(s) is/are likely to be causing the browning of the leaves?


Im walking on pretty thin ice but I feel more confident guessing what deficiency it -isnt-. 
It doesn't look like iron, magnesium or nitrate deficiency to me, only based on my personal experience with my own java ferns.
The silvery grey areas are very interesting, is the picture true to life? Do they have almost a purple hue? If so, could it be phosphorus?

I am just guessing so take it with a grain of salt

Are you able to see if the affected leaves are old or new leaves?


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## jaypeecee (26 Oct 2021)

Hufsa said:


> Do they have almost a purple hue? If so, could it be phosphorus?


Hi @Hufsa

Phosphorus deficiency is, in my opinion, the most likely explanation. It's very likely that stored phosphorus in the Java Ferns has now been depleted. I don't know why it's taken me so long for the 'penny to drop'!  Being epiphytes, the Java Ferns are unable to uptake phosphate from the substrate*. BTW, the browning leaf edges do not have a purple hue. It's very much a rust red/brown.

* and this tank does not have any substrate!

JPC


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## John q (26 Oct 2021)

jaypeecee said:


> Phosphorus deficiency is, in my opinion, the most likely explanation


Mine too, but maybe I've missed the boat on this one. 

If your hypothesis is based on "phosphate causes cyanobacteria" then I assume you're feeding the tank/plants everything except this?  If that's not the case, then please correct me on this. 
However if this is the case then I would suggest the plants are suffering phosphate deficiencies?


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## jaypeecee (26 Oct 2021)

John q said:


> If your hypothesis is based on "phosphate causes cyanobacteria" then I assume you're feeding the tank/plants everything except this? If that's not the case, then please correct me on this.
> However if this is the case then I would suggest the plants are suffering phosphate deficiencies?


Hi @John q

Thanks for the feedback.

I don't think it's as simple as X causes Y. For quite some time, I've been trying to identify the factors that give rise to the growth of the species of Cyanobacteria that grows in our tanks. Please take a look at:






						Cyanobacteria Identification - At Last!
					

Hi Folks,  Like many other aquarists, I have had cyanobacteria (aka 'BGA') grow in my tanks. And I started reading about this stuff. Of course, I initially thought BGA was algae. Why else would it be known as BGA (Blue-Green Algae)? But I later discovered that it's not an algae at all. It's a...



					www.ukaps.org
				




If my memory serves me rightly, Tom Barr has also said that Oscillatoria is the most prevalent in hobbyists' tanks. I'll check this out as I think it's on _The Barr Report_ forums. As I have concluded above (post #38), it's now pretty obvious that some of the Java Ferns have got to the stage where phosphorus has been depleted.

JPC


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## John q (26 Oct 2021)

jaypeecee said:


> Thanks for the feedback.
> 
> I don't think it's as simple as X causes Y.


I get that @jaypeecee  but your opening line in this thread was this.


jaypeecee said:


> Based on a lot of observations and measurements, I'd like to put forward a suggestion/hypothesis. It is this:
> 
> Perhaps cyanobacteria (BGA) and algae need _inorganic_ phosphate (orthophosphate)/PO4


I'll suggest they also need a number of other nutrients to survive, omit any one of them and the cyanobacteria will reced.

Maybe this hypothesis is above my head (which is probable) just trying to understand what exactly it is you're suggesting is the cause of algae/cyanobacteria.


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