# Where did BGA = low nitrate myth arise?



## Tsigoloeg (Nov 5, 2006)

I apologize in advance for sounding like a cantankerous old coot. 

Can anyone point to a definitive scientific (or at least putting on airs of such) work that is readily available? Seriously, did someone just read somewhere that some cyanobacteria have heterocysts that fix nitrogen and thus all must thrive in low-NO3?

I only ask because I keep seeing this over and over on this forum, yet when I starved my 29 gal of nitrate the only visible minor colony of cyano in the tank, which rode in on a lotus I had just purchased, went away.

Now don't read too much into that fact as a causitive agent either, as I also starved PO4 at the same time, probably other elements as well but I wasn't paying attention to molybdenum etc. But I think that if the stuff really flourished in low NO3 environments as a cause-effect relationship, my tank would be smothered in it.


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## plantbrain (Dec 15, 2003)

Tsigoloeg said:


> I apologize in advance for sounding like a cantankerous old coot.
> 
> Can anyone point to a definitive scientific (or at least putting on airs of such) work that is readily available? Seriously, did someone just read somewhere that some cyanobacteria have heterocysts that fix nitrogen and thus all must thrive in low-NO3?


The genus _Oscillitoria_ is specific and what infest our tanks, and is a non heterocytic forming BGA. Rather than assuming low NO3 etc, the size difference alone in all algae point to this.

Algae and BGA's are not limited by N in planted aquariums.
Relative to plant, they have several orders of magnitude less demand for N.
Plants on the otherhand grow poorly/not at all, stunt etcwhen NO3/N is very low.

Many suggested low NO3 and heterocyst, I have always strongly argued against it because I actually can do algal and cyanobacterial taxonomy.
Several other reseach folks also have verified the taxonomic determination in the same lab I was working in. 
It's a very common FW genus.
See Sheath et al.
Also, try Google scholar for references.



> I only ask because I keep seeing this over and over on this forum, yet when I starved my 29 gal of nitrate the only visible minor colony of cyano in the tank, which rode in on a lotus I had just purchased, went away.


I have induced NO3 many times by starving the tank.
I confrmed it with a calibrated test kit.
Still, it does *not* say what causes BGA to grow and bloom.

You will not find a reference that says X causes _Oscillitoria_ to grow. You might find some corrleation, not much is done with this genus with respect to aquatic macrophytes.

When deciding what consititutes a good fair test of whether something works or not, you first need a control and base line to compare to don't you think?

A 1/2 dead colony of a nice healthy mat would work best for comparing things and treatments to????

Obviously a nice thriving mat of BGA.

When inducing BGA, what would be a better baseline to induce BGA in a tank?
One that has good plant growth for the the last few weeks, no signs of issues, etc, then you manipulate one variable at a time or would a tank that's on the border line with little control of test, some different species here and there of algae(A sign of something wrong in the tank to begin with)???

Most hobbyist are not able to discern and implement a good test for algae.
Most lack the control and the ability to have baseline.
Most that complain are those that do have issues already:icon_idea 
The ones that do not have the issues etc tell them what to do, but they think they already have done it(they made this assumption very often).



> Now don't read too much into that fact as a causitive agent either, as I also starved PO4 at the same time, probably other elements as well but I wasn't paying attention to molybdenum etc. But I think that if the stuff really flourished in low NO3 environments as a cause-effect relationship, my tank would be smothered in it.


Many tanks do well with low NO3/PO4.
How confident are you that the tank is really low in NO3 and PO4?
What types fo testing methods, calibration methods do you use?

I know I can induce BGA in most tanks, but perhaps not all. I also know that virtually every tank's substrate sample I've ever looked at had _Oscillitoria_.

I think _Oscillitoria_ is responsive to the plants, perhaps a biochemical stress they give, or form of leachate that plants give off when stressed.

I've also seen BGA bloom when the water is very high in organics and the filter's not been cleaned for a long time. 

But in each case, I've found counter examples also where _Oscillitoria_ did not grow as well.

Still, the chances of folks having BGA due to NO3 is well correlated if you tally the total BGA reports vs the solved cases.

I have not had a BGA issue in many many years.
Enough to know that if due to chance alone, I should have had BGA if it where not due to KNO3 dosing.

Some have suggested it is K+ rather than NO3 from the KNO3.

Could be.

But generally, the evidence based on testing our tanks with calibrated test kits seems to point more to NO3 as the main cause, as few if any folks test their K+ that I know other than myself.

I'm afraid there is just not a lot of scientific research done with many algal species and BGA's in the contect of our tanks and plants etc.

There are many unknowns and correlations, we can say what it is not(falsification), but it's much harder to say what it is(verification).

I've found that doing the blackout and KNO3 dosing etc takes care of it and reinfestations do not occur each time I've done it for a friend or on my own tanks that I've induced BGA in. after 20X I start to feel comfortable about a method to control it.

Still, it's not a silver bullet either(Growing plants well seesm to be the only silver bullet there is). Some folks will always have algae issues for one reason or another. Some will not follow part of the method etc.
We make mistakes and often learn more from such mistakes.

You need to do some background reading, test and set some test up first before you argue. Thus far you have not presented much in the way of new support against low NO3 stunting plants and it might be low POI4 as you acknowldge, thus already you lack the control and have not actively tested/calibrated the test kits nor set up an experimental design.

I do encourage this. Make sure to verify your PO4/NO3, timing, the health before and after, and so forth when you do it.

Try and not base things on potentially confounding factors like not dosing and assuming that means the NO3 is low.

It might not be.
Or the PO4 levels, K+, levels or traces, CO2 etc.

I see the same stuff folks do also, but I knwo I need to be careful and make sure what I see is somewhat reasonable and I can rule out things like CO2, 
PO4, K+, etc.

All science has some degeree of doubt and should be viewed critically.
But it does work very very well nonetheless.

Regards, 
Tom Barr


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## Tsigoloeg (Nov 5, 2006)

> The genus Oscillitoria is specific and what infest our tanks, and is a non heterocytic forming BGA.


Yes, thus the "some...all..." reference in my post. In any event I was probably overspecific since some cyanos, including _Oscillatoria _species, have been shown to fix N2 w/o heterocysts.



> I have induced NO3 many times by starving the tank.


Did you induce NO3 or did you induce _Oscillatoria_? 

And no, I'm not trying to be an ass thinking I'm pointing out a typo, I'm actually curious if this is what you meant. E.G., there are published reports of limnic eutrophication resulting from nutrient addition of N and P, but not directly a result of algae blooming on them, rather hetero bacteria blooming thus oxidizing C and providing CO2 to the algae. So were you trying to point out that you induced cyano by starving the tank, or point out that you increased NO3 by starving the tank?



> You will not find a reference that says X causes Oscillitoria to grow.


I wouldn't expect one, as the genus contains too many species that thrive in diverse environments. I might expect one that says _O. [species] _thrives in this range of conditions.
...
I know about/agree with you about the need for proper control in the design of scientific experiments, the testing methods, etc. I can assure you I am not a slouch. This is not really the issue here and isn't particularly germane, but I will address a little at the end since you did question me about my specifics.

Here is my point: time and again, someone will post on the forum "I have this algal problem" without bothering to do a simple search, and some well-intentioned and fairly patient person will respond with the boilerplate "BGA = low nitrates." Which you admit is based on: 1) a correlation (qualitatively stated as "strong") of solved cases to reports of cyano, and 2) a lack of convincing data regarding the real culprit being a) K or NO3 deficiency, b) the death of cyanos/algae via blackout releasing their stored nutrients to the plants, or c) another part of the unspecified "etc" you use as a treatment. All of which I could just as well criticize you about lack of control in these anecdotes as you argue with me about mine.

Then the original poster may come back and say "my nitrates are 20-30 ppm" and there'll be me who says "I have no BGA and my nitrates are basically zero (meaning unmeasurable with available equipment)." These are falsifications of the hypothesis. For in order to be true, an hypothesis should match all observations. And, yes, I know we are dealing with biological systems here so the best science we can hope for is matching X to Y compared to control group Z and nothing will be 100%. But the other fun aspect of an hypothesis: *It also needs to make testable predictions.* An obvious one in this example, "Plants will show signs of nitrogen deficiency." Do they? Another one would be "Adding more NO3 to the exclusion of any other nutrient will alleviate the cyanobacteria." Does it? 

I think the thing that gets me most is the absolutist nature of the statement "BGA = low nitrates." You insinuate that you think it is more a reaction of the plants to being stressed rather than a particular condition, yet from my interpretation of your post as a whole you still seem to defend the overall notion of lacking NO3. I am confused with the inconsistency. Now there is nothing wrong with saying "If you have BGA, check NO3 levels, as this has shown to be a common indicator of plant stress inducing a BGA outbreak." But "equals?" No.

Regarding my confidence in determining NO3 levels: yes they are based more on just "not dosing" ferts. I don't have my own KNO3 supply, so here is how I "calibrated" my NO3 test kit(s). First, I tried kit#1. It read 0 and I expected it to read higher than that, so I thought to myself "Oh, this kit is too old and doesn't work properly" so I went and bought kit#2 of a different brand. Same result = 0. A little "wtf" went through my head. So I brought in a sample to the LFS, they tested with a dip strip. Result = 0. So I figure, if the chances are that all 3 different kits provide the exact same false reading, the universe has it in for me and whatever consequences I have coming as a result of believing them are unavoidable. But, using your words, generally the evidence points towards my NO3 = "0."

Regarding the cyano 'infest' I had: I bought a lotus plant from a LFS that had a mat of cyano in the tank (mine was clean). This was very soon after I had added water to the tank (within 2 weeks). A few weeks later, a small mat is on the stem of one of the lotus leaves, and over the course of the next two weeks the mat got larger. I think that qualifies for a healthy mat. Then my plants, having been recently introduced, took off, which used up the nutrients in the water column; then the cyano went away, the 'GDA' went away, the diatoms went away, and the stuff that vaguely resembles BBA that only inhabits my slate diminished considerably. I say vaguely because it never got large enough to really be beardish or brushlike. This all corresponded to vigorous and healthy plant growth, which (I admit is an assumption) explains the lack of N and P in the water. That was actually my goal. And I should add that I used an inappropriate term in 'starve' regarding N & P with my plants...they actually have those elements available via root tabs.



> Thus far you have not presented much in the way of new support against low NO3 stunting plants


[sic]

I presume you meant stunting cyanos, else this is a non-sequitor. Lets please note here, for the second time, that *I have not and am not claiming that low NO3 removes cyanos.* And furthermore let me note that am I not criticizing or denying that you've had success with your particular treatment method! *My whole point is that the CW of low NO3 as the primary or direct causitive agent leading to the infestation of cyanos is at best an oversimplification.* I just see no reason to tell a person who asks, e.g., "My NO3 is < 5.0 ppm, is this a problem?" that they should expect an outbreak of cyanobacteria. Or telling a person with "BGA" that that is definitively what their problem is.

Thanks for the input.


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## plantbrain (Dec 15, 2003)

Tsigoloeg said:


> Yes, thus the "some...all..." reference in my post. In any event I was probably overspecific since some cyanos, including _Oscillatoria _species, have been shown to fix N2 w/o heterocysts.


Not the species we have though..........do you know how the other species do this without heterocyst?



> Did you induce NO3 or did you induce _Oscillatoria_?
> 
> And no, I'm not trying to be an ass thinking I'm pointing out a typo, I'm actually curious if this is what you meant. E.G., there are published reports of limnic eutrophication resulting from nutrient addition of N and P, but not directly a result of algae blooming on them, rather hetero bacteria blooming thus oxidizing C and providing CO2 to the algae. So were you trying to point out that you induced cyano by starving the tank, or point out that you increased NO3 by starving the tank?


The BGA, not NO3.



> Here is my point: time and again, someone will post on the forum "I have this algal problem" without bothering to do a simple search, and some well-intentioned and fairly patient person will respond with the boilerplate "BGA = low nitrates." Which you admit is based on: 1) a correlation (qualitatively stated as "strong") of solved cases to reports of cyano, and 2) a lack of convincing data regarding the real culprit being a) K or NO3 deficiency, b) the death of cyanos/algae via blackout releasing their stored nutrients to the plants, or c) another part of the unspecified "etc" you use as a treatment. All of which I could just as well criticize you about lack of control in these anecdotes as you argue with me about mine.
> 
> Then the original poster may come back and say "my nitrates are 20-30 ppm" and there'll be me who says "I have no BGA and my nitrates are basically zero (meaning unmeasurable with available equipment)." These are falsifications of the hypothesis.
> 
> ...


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## Tsigoloeg (Nov 5, 2006)

> Originally Posted by Tsigoloeg
> Yes, thus the "some...all..." reference in my post. In any event I was probably overspecific since some cyanos, including Oscillatoria species, have been shown to fix N2 w/o heterocysts.
> 
> Not the species we have though..........do you know how the other species do this without heterocyst?


EJ Carpenter and CC Price (1976) Marine oscillatoria (Trichodesmium): explanation for aerobic nitrogen fixation without heterocysts. Science, 191(4233): 1278-1280 



> Sure, they might do fine with very low NO3 in the water column, but they may have plenty of NO3 in the substrate.
> 
> In that case, the plants are still fine, it's *not solely the water column that controls the BGA, it's the interaction between the N limiting of the plants and BGA * (emphasis added) ...


Well, finally there it is..."admission" to the source of my protestation to begin with. Everyone is going around yelling all fish are trout because they know all trout are fish. 

(Ignoring the phyllogenetic determination that there is no such thing as a fish).



> ... and perhaps the NO3 levels as well.


It is hard to let go of a favorite notion, and there is a lot to be said about the power of intuition in leading us down the correct path (and the opposite). I respect the amount of work and the observations made. I don't doubt that you've had success with your method, and commend you on your help to the hobby.

I don't doubt there are situations when low NO3 is responsible for "BGA." Many fish are actually trout.

But you keep bringing up methods of science, and using them correctly. Yet you defend your intuition (at least within this thread) using solely correlation, anecdotal evidence, a biased sampling population (i.e., a limited-scope, non-random set of observations), lack of controls in fertilizers (dosing 2 of the 3 main macronutrients claiming only one matters), lack of controls in conditions (e.g., using blackouts, antibiotics:icon_excl , and filter cleanings), not testing further predictions of the hypothesis, and using assumptions to justify ignoring contradictory observations (the whole test kit red herring).

On that last point I will grant you a mulligan in regards to the observation I cited of "BGA" with 20-30 ppm NO3. I also have seen an old NO3 test kit read 20-30 ppm when testing distilled water, and I am not going to spend time defending someone else's data. 

However, you used a similar situation to justify doubting my reading of "0" ppm. Apple, meet orange. If you're going to use an assumption based on prior experiences to ignore data you probably ought to make sure the comparision is homologous (e.g., don't cite false high-reading examples as justification to ignore a low reading). As well, my test kits read 0 on distilled water, 3 test kits read the same value on my planted tank, and my 2 test kits read 0 < X < 10 on my non-planted (again cyano-free).



> And just because you had a case where no BGA was induced, your test kits are also suspect.


That is called circular logic. Add to the 4th paragraph above.



> Now you are getting yourself in such a pickle.


Welcome to the pickle jar.

Again, thank you for your input. The basic questions I first brought up are now satisfactorily answered (albeit some in a roundabout fashion).
Cheers,
Tsig


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## plantbrain (Dec 15, 2003)

Tsigoloeg said:


> EJ Carpenter and CC Price (1976) Marine oscillatoria (Trichodesmium): explanation for aerobic nitrogen fixation without heterocysts. Science, 191(4233): 1278-1280


And we have *marine* Oscillatoria huh?
You need to be more specific.

A bad reference is still a bad reference and offers no direct support.
Marine BGA out in the middle of the ocean far far away from N souces(very unlike even a spartan system for FW algae) are nothing like the juicy rich aquariums full of leaching plants, fish waste etc.

You cannot limit BGA in our aquariums that have plants and fish with nutrients.

You assume that because it's in the same genus, that it's the same?
Big assumption.

So what was "the mechanism" that they sepeculate allows them to do this N2fixing?



> But you keep bringing up methods of science, and using them correctly. Yet you defend your intuition (at least within this thread) using solely correlation, anecdotal evidence, a biased sampling population (i.e., a limited-scope, non-random set of observations), lack of controls in fertilizers (dosing 2 of the 3 main macronutrients claiming only one matters), lack of controls in conditions (e.g., using blackouts, antibiotics:icon_excl , and filter cleanings), not testing further predictions of the hypothesis, and using assumptions to justify ignoring contradictory observations (the whole test kit red herring).


I have never said I found causation. 
Now you are holding me to the same rigor of a peer reviewed article in journal, that's not what I've done nor ever claimed to have done.
I'm not ignoring alternative causes, nor are what you saying in anyway contradictory to what I nor others have observed.

And lesty take a look at your own hypocrisy here:
1.You used one tank, and you talk to me about "bias sample population"?
I have hundereds to my credit.

2. My controls for treatment(note, this is different than suggesting inducement, you seemed to have muddle these two): the 3 day blackout is pretty simple and that is where I've done some work. 
Inducing is another issue entirely: limiting NO3. You never, curiously, addressed the substrate source for NO3. Controls on filter clening is related to BOD, something that can be tested for, I have not yet, but when I have some free time, I will. I am not getting paid for any of this:icon_mrgr 

3. I have used correlation and ruled out other possible causes(by testing my hypothesis to the best I can, doing this for free) and whittle it down to a couple few main hypothesis and they do seem to work quite well:icon_roll 
You? You cannot even calibrate a test kit, nor address the other source of nitrogen.

4. Actually, I do/did have controls in place for fertilizer. I calibrate and have some rather nice Nitrogen testing equipment. I know the replcement make up water and the concentration of the ferts. No, the ferts are not all precisely stable, chemostats are PITA to keep up, and not applicable nor needed here, you can argue they are all day, but no one is really going to listen till you demostrate that all the moaning you are doing is really needed here and practical for the hobby. In an ideal world perhaps.
So where was your controls?
Where in any of this have you ruled out other confounding issues ti your vs my own observations, which clearly had a lot more rigor and testing than yours?

Do as I say, not as I do?

5. I've tested further predictions more than you certainly.
And more than most. 
Proving causation is very difficult.
I speculate but at least I have some understanding of algae inducement.
You have none near as anything you have said thus far suggest.

But.......I ruled out things and was left with only a few alternative hypothesis. You have not ruled out much of anything.
Nor have you offered up any new more reasonable hypothesis to explain the observations is a controlled test.
Nor have you done any test.
I can punch holes in anyone's paper and pick it apart.
I can do the same to any test procedure.

At some point you have to say enough is enough. 
If you think you can do better, why not just do it rather than moaning here?

Knock yourself out, or are you the arm chair aquarist who whines, then *do nothing themselves*?

You over looked some rather basics things, I opted not to spend several months in intensive studies, $ and testing to prove this(nor am I getting paid for it I might add) but addressed many of the more basic easier to deal with issues. I tried it, it works.
It does not rule out everything, nor do I expected it to. 



> On that last point I will grant you a mulligan in regards to the observation I cited of "BGA" with 20-30 ppm NO3. I also have seen an old NO3 test kit read 20-30 ppm when testing distilled water, and I am not going to
> spend time defending someone else's data.However, you used a similar situation to justify doubting my reading of "0" ppm.


No I did not.
The folks that had such readings I used my own calibrated test kits to verify such whack data. They where in fact, whacky.
Other folks later calibrated(ahem.....*unlike you*) and found them to be off. Quit comparing yourself to those that do the work and check things.
If you have, then you got something to say.



> If you're going to use an assumption based on prior experiences to ignore data you probably ought to make sure the comparision is homologous (e.g., don't cite false high-reading examples as justification to ignore a low reading). As well, my test kits read 0 on distilled water, 3 test kits read the same value on my planted tank, and my 2 test kits read 0 < X < 10 on my non-planted (again cyano-free).


Do not tell me what I ought to do here.
You are too lazy to do a test, calibrate anything and want to complain and tell me what I _ought to do _about it here?

You never addressed N source in the substrate.
Sort of major issue you based your entire assumption on.



> Again, thank you for your input. The basic questions I first brought up are now satisfactorily answered (albeit some in a roundabout fashion).
> Cheers,
> Tsig


I am glad you figured this all out on your own with using a non calibrated test kit, one tank observation, found that science nor testing is ever abosolute, never addressed your substrate, but but of course....took the time out to
question me and what I ought to do.


Regards, 
Tom Barr


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## fresh_lynny (Mar 9, 2006)

nice exchange.... 
very informative...some good points brought up


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## plantbrain (Dec 15, 2003)

I think there is more to do here regarding BGA inducement(I never suggested otherwise) and seeing if such other hypothesis besides low NO3, might induce BGA.

But the poster has not suggested _any_, nor suggest _how _a test might be done for the hobbyists, nor acknowledged the substrate role, nor the test kit calibration(and what is the organic fraction vs the inorganic fraction of the Nitrogen, I can go on and on as well)?

I do not trust what I see nearly as much as the poster.
So I go about checking things to make sure, within reason and resources, to see if I can rule my hypothesis out or not.
I try it, and it works, other's try and it also works.
I repeated the test many times.
I see BGA and stunted plants due to low NO3 very well correlated and am able to help folks without even knowning their NO3 levels.

Maybe I'm just lucky.
But it does not suggest there are other factors involved in inducing BGA.
That's the real issue, what induces BGA?

Not what gets rid of it.
Rather, what keeps it from growing to begin with?

That's a different approach and question.
Few hobbysits ever try to induce algae on purpose.
That's a lot more telling when you go about things that way.



Regards, 
Tom Barr


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## Tsigoloeg (Nov 5, 2006)

1) Regarding the whole _Oscillatoria_/heterocyst reference, I was merely attempting to answer what I considered a genuine curiosity on your part. I didn't figure you to misinterpret any of that as some sort of attempt to prove any point on my part, and then to turn it around as an attack of sorts. If you had actually read carefully my original post I lamented the fact (I have actually read this before, I just can't put my finger on the source atm) of people claiming that some cyanobacteria fix atmospheric N2 thus leaping to one giant conclusion that any cyano can fix N2 and thus all cyano thrive in low N (and therefore low NO3) environments.

Go ahead, scroll up and re-read, then ponder for a minute.

2) Again, going back to my original post, I asked what the evidence was that low NO3 = cyanos. None was offered by you, ever.

Instead, what I got were insults. "You don't do this right. You assume this wrong. You need to learn how to read." Etc. Again, no evidence. People who have none often resort to smears and character assails to deflect that attention. Why would it have been so hard to just state your case, or point me to where you've done it before? You obviously do apparently have some.

Over the course of these posts I managed to piece together what it was you were using for your evidence. That was the main question to which I claimed to have received my answers roundaboutedly.

a) correlation
b) anecdotal
c) qualitative

I may as well be reading about a miracle cure for male pattern baldness on a website advertisement.

And the sad part about all this is I would've been content with the answers of a, b, and c had they been presented in a respectful fashion.

3) You accuse me of hypocrisy by attempting to draw a broad conclusion and type words into my thread suggesting that I claim to have in some way discovered a new mechanism to treat CYB in aquaria, or perhaps that I have claimed to discover some new inducement technique. I have *EXPLICITLY *(and multiple times at that) disavowed that notion including the original post. In retrospect, given your complete refusal to acknowledge these sentences of mine I shouldn't be too surprised about the lack of ability to discern the meaning of my providing the reference as explained above.

I am typing the following out once again here, one more time, but I question if the result going to be any different? How about if I put these bouncy things next to them?

:bounce: *I have not and am not claiming that low NO3 removes cyanos.* :bounce: 

Did that help?

The only thing I did was question what I saw and read, which leads me to:

4) This test kit calibration argument would actually hold water if I were in fact attempting to place some constraints on causation (or the reverse) of CYB. Read #3 above again and see if it sinks in this time.

That being said, I made plenty of effort to calibrate my readings *to the level of accuracy being asked of them*. <tap - tap- tap - ... Is this thing on?> Like you, I don't have an unlimited budget of $ or time to deal with this distraction. So if 3 tests give the same result on 1 sample, 2 give the same result on another sample (with known concentration) and the same 2 give a matching result on a 3rd sample, I have confidence that they are working to the degree that I require them to be. To insist that they aren't is grasping at straws and nothing more. 

And, here I go again, stating one more time when I know full-well it won't sink in...I'm not testing the difference b/w 1 and 5 ppm, not even 1 and 20 ppm. I'm testing the difference b/w detectable amounts and not-detectable amounts. And I never claimed anything to the contrary.

To insult me as to being gullible and believing everything I see is absolute hogwash. That's why I had it tested, not twice, but three times. It is also why I asked what was the evidence for this in my original post.

5) The deal with the substrate source of ferts is thus: In my original post, what triggered this whole mess, what induced me to write, is the testing of water. After all, I suspect it is a very small % of the hobby that tests their substrate for NO3. CYB have no roots. They can't utilize substrate sources of N (or other nutrients) unless they are actually ON the substrate or unless the diffusion gradient is positive above the sediment-water interface. In which case, given the rate of water turnover in the filtering systems in our aquaria, that is basically the level of NO3 present in the water column.

So it was the claim of lack of NO3 in the water, and not the lack of NO3 in the entire tank or known universe that I was questioning. I tried to offer a _mea culpa _on reading too much into it in that respect. And we were even coming to a mutual (or so I thought) understanding of the situation given our different perspectives in this regard: you assuming an inert substrate, me not assuming such. It came out of your fingertips not once but twice that it is nitrogen deprivation and not NO3 _per se_.

But instead you continue to wedge, basing the evidence I see to be lack of comprehension of most anything I've actually written, and then yourself writing things into what I have typed and then bemoaning those made up facts. All the while piling on insinuated and explicit insults.

And the other point I've made repeatedly is the way this thing has become such an oversimplification. Such that people with only fish and plastic plants will probably soon read it and dose nitrates in their CYB infested tanks. To which I get to read once again that you agree, *but*, have to insist on pointing out that it is not due to anything I wrote, which you think I wrote, that I did not actually write.



> nor are what you saying in anyway contradictory to what I nor others have observed.


Then why the hell just not state that to begin with??

In my original post I tried to indicate that I was not trying to be as gruff as what comes across when things are written and not spoken. Once again I invite you to scroll up and read what has actually been written and not what you think is being said. I'm sorry if by your eyes I seem to have 'attacked' you. I tried numerous times to point out the opposite (once more, scroll back). I apologize for any offense taken. I have every right to question, I had sound basis on which to question, you admit my observations were not contradictory, but you only assailed me by using examples that I pointed out did not make sense or were conflicting to your own prose. The answers to my questions were (finally) forthcoming, I learned where you were coming from at least. If not respectfully or directly, at least satisfactorily. One doesn't learn properly without questioning as well as being questioned.

Sincerely,
Tsig


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