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A Fresh Look At Preventing Algae?

hypnogogia

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For a lab study this would of course be right. It could also be looked at as applied research and data is collected on many more variables, e.g make of light, lighting period, water parameters, water changes and then they can be controlled for statistically.
 

JoshP12

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Hi all,

I like this conversation.

It seems that we are grounded in the Redfield ratio; I found < Tom Barr's thoughts on the matter >.

I think the crux of the ratio has to do with the plants (obviously right?). I am not sure how terrestrial thoughts apply to aquatic thoughts - nonetheless, they are thoughts that could potentially lead somewhere.

I don't have < this paper >, but I read the abstract - this was neat:
Four conditions lake water, water and algae, water and sediments, and three objects together were conducted to investigate the effects of cyanobacteria growth on the migration and transformation of phosphorus. Results showed a persistent correlation between the development of cyanobacterial blooms and the increase of soluble reactive phosphorus (SRP) in the lake water under the condition of three objects together.

Again, < no paper > , but here is part of the abstract:

1) Phosphorus deficiency often limits the plant productivity because of its low mobility in soil and the root system. Its low mobility may retard the ability of a plant to acquire this nutrient.

2) Application of phosphorus in soil not only promoted its mobility into the plant system but also increased the plant growth significantly.

3) Leaf area and leaf area ratio were also increased.

Ok, that paper is about radish, so let's not make crazy conclusions; however, this may frame a concept as to why my ludwigia and my rotala < look like they are on steroids >.

I've been thinking more about nutrients lately and it seems that phosphate has this ability to increase nutrient demand immensely. I don't know why (but would love to know!).

The cyano link seems to be, perhaps, that the excess phosphates (throwing the ratio) bottoms all nutrients (including CO2) and nitrates (low nitrates and cyano?) - bringing on deficiencies. Those deficiencies brood an unhealthy system ... and algae blooms. So keeping your phosphates low can reduce your overall demand of nutrients (in particular CO2). If you don't have the light to drive phosphate uptake, then I suspect that, so long as nitrates do not bottom out and are still accessible, you won't get cyano (and if everything else is set, you won't get algae). Or if every hour, you dosed .5 ppm of nitrates (or whatever), it would be fine. I also wouldn't be surprised if Cyano can utilize phosphates in a way that plants cannot.

This does give credence to the connection that fertilizer run-off in lakes gives rise to algae. If we could inject CO2 into lakes, those ferts wouldn't cause any issues. But many local lakes experience algae blooms after intense run off - because perhaps phosphate is more powerful than CO2!?!?!

There is definitely something with the idea and the link to cyano:

https://edmontonjournal.com/news/lo...ontrol-in-lakes-is-key-to-reduce-algal-blooms
https://www.cbc.ca/news/canada/edmonton/blue-green-algae-alberta-lakes-1.4255904
https://open.alberta.ca/dataset/3e8...b5f-4c92-a455-2407ff5233ed/download/090-4.pdf

Some thoughts for now!

Josh
 

Geoffrey Rea

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The ecological validity of a controlled environment, like a jar test, is questionable. Would suspect all you would find is that greater inorganic fertilisation (concentration) in general leads to a larger bacterial colony of BGA without anything else competing for resources in a controlled environment.



As for in tank you would expect BGA to appear in lower oxygen environments; against the glass in the substrate, very low flow areas, amongst thick rooting of carpeting plants or in a lowly planted tank like a moss only scape. It’s niche area in an aquarium is low oxygen areas with low flow. Not sure anyone is really debating this point who has run enough aquarium’s in their time.



Porous rock as a base layer in the substrate may help increase flow to circumvent this, as might avoiding planting right against the glass so roots don’t choke the area against the glass in the soil where there’s an abundance of light and lower o2.



With regards to an aquarium system, in agreement with Tom Barr in that concentration rather than ratios, light intensity and availability of Co2 all marry to create the potential growth capability of the plants in that system.



A reasonable prediction of altering N and P concentrations in general, regardless of ratios, is that what you’re observing with regards to BGA progression/regression in a tank, is the relationship between the concentration of fertiliser to the amount of dissolved oxygen created in that system by the plants photosynthesising, not a relationship between fertilisation and BGA. A high level of dissolved oxygen, as a byproduct of lots of photosynthesis, creates a hostile environment for BGA in an aquarium. This is evidenced by healthy high tech systems that run long term with BGA in the substrate along the glass, but not from the substrate to surface.
 
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As for in tank you would expect BGA to appear in lower oxygen environments; against the glass in the substrate, very low flow areas, amongst thick rooting of carpeting plants or in a lowly planted tank like a moss only scape.
The tiny pockets of BGA that I got were all within an inch of the surface, directly in the spray bar outflow and directly underneath the area of most vigorous surface agitation!
 

dw1305

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Hi all,
I'll start by saying I have absolutely no idea why EI works (it was developed by @plantbrain), but I'm willing to accept that it does. Before I joined this forum if some-one had described EI to me and then asked if I thought it would work, I would have told them that it had a "Snowball in Hell's" chance. The same applies to <"GSA and raising PO4--- levels">, I don't know why it works, but I'm willing to accept that it does.

If you want my best guess the reason why any of <"these, widely differing approaches"> "work", it is the <"oxygen one"> alluded to by @Geoffrey Rea.

I would tend to agree with @hypnogogia, @Siege and @Geoffrey Rea. I think there are <"just too many variables"> to be able to quantify exactly what makes a tank "successful". You not only have plants that are adapted to a wide range of <"nutrient and light levels">, but you also <"have algal"> assemblages that reflect <"differing nutrient levels">.

If someone really did want to have a go at answering the question (@jaypeecee, @Dr Mike Oxgreen )? If you could find sufficient scientific studies that quantify plant health, algal growth, dissolved oxygen and nutrient levels you could use a <"data-mining approach"> to attempt to isolate the important factor(s) using <"bayesian metadata analysis">.

As for the <"redfield ratio">, my guess is that it has some relevance for marine phytoplankton blooms, but after that things are a lot less clear.

cheers Darrel
 
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Geoffrey Rea

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The words chosen were selected carefully.

you would expect BGA to appear

It will appear in low oxygen/flow areas first. However, if the whole system is being run sub-optimally for plant growth continually, then with time there’s nowhere it won’t colonise as long as there’s light:

1594982896122.jpeg


Photo credit: AQUAdesign

If you can afford to and you can tolerate the smell it’s worth letting it collapse a planted tank without livestock just to see how it behaves across time. It isn’t just progressing, it’s adapting the whole system to its preference.


If someone really did want to have a go at answering the question (@jaypeecee, @Dr Mike Oxgreen )? If you could find sufficient scientific studies that quantify plant health, algal growth, dissolved oxygen and nutrient levels you could use a <"data-mining approach"> to attempt to isolate the important factor(s) using <"bayesian metadata analysis">.

This would be a really nice meta-analysis project @dw1305
 
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kilnakorr

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Well, I found my NO3 test to be non working.
This only proves, once again, that these tests shouldn't be used solely.
I've been having some issues with my tank and lost track of ferts when upping the waterchanges, and used the test just to make sure I didn't go to low (making sure issues wasn't fert related).

Well, here are the tests:
20200717_134202.jpg

Above image is RO water showing around 12-15ppm (picture is a little darker than it really is).

20200717_134644.jpg

Above picture showing unknown but VERY high NO3 solution (500+ppm), reading just below 25 ppm.

Completely worthless tests!

I went out and purchased som new tests, as I was curious:

20200717_145541.jpg

Much better! RO to the left, showing less than 0.5 pp. Unknown solution to the right showing above 240ppm.

But what about my tank? I was already thinking N was low, so last night I dosed 8 ppm dry KNO3 in the tank, and the ussual dosing of 3ppm was dosed during the night. The test:

20200717_145908.jpg

Around 5ppm!

Reasons to add all of thid in this thread?
If the Redfield ratio had some truth in it, I would be swimming in BGA.
I have had 0-5ppm NO3 for weeks, but been dosing PO4 back to 1.5 ppm with waterchanges along with the usual dosing.

I haven't tested PO4 yet, as my digital reader seems to be decent (+/÷10).
 

JoshP12

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The same applies to <"GSA and raising PO4--- levels">, I don't know why it works, but I'm willing to accept that it does.

I think you nail it in < this post >; certainly without extensive testing, we cannot say for sure. However, after my experience with extremely < out-proportioned potassium >, I have to say that I have accepted cation interference - which is all grounded in concentration gradients of nutrients. Every post I read that has GSA is from EI users. When I dropped potassium, my GSA on the glass didn't come back, nor did it continue to get worse on my unhealthy buce 🤔.

If we follow Mulders (and I chose to add the one below fro MSU, though I see some different ones - which is unclear to me - where the antagonism are not the same):
1594992812960.png


Zinc, Copper, Iron, Potassium all inhibit phosphate. Think of the EI trace dose - I've got no numbers - but it's well over what the tank needs (as it should be in the spirit of EI).

note:
1) We can discuss here ion exchange INTO the substrate.
2) We can also discuss source water.
3) Light - HIGH light means more nutrients (including CO2) are being absorbed).

Is it possible that the micro nutrient accumulation (and in every tank is different due to 1 and 2 and 3) over a period of time inhibits phosphates. It is certainly not day 1 or 10 or 30 that gave rise to GSA (at least not in any tank I have ever had - albeit not that many - or in posts that I have read from a variety of forums) ... it is later. It is only after a period of time that the higher phosphate dose is needed. We know nutrient accumulation with consistent water changes will plateau after several weeks ... that plateau is the baseline and it is at that point we see GSA pop up ... as a result, we need more phosphate to overcome the baseline of nutrient accumulation (I am not talking toxicity).

The deficiency of phosphate in the plant is not SO large that it is demonstrating dying leaves but it is large enough that pockets can have GSA. I mentioned in that excess potassium post that:

Interesting note the excess potassium did not allow algae to attack my fast growing plants - even Ludwigia (which is slower then rotala), s repens, etc. However, my unhealthy buce was having a persistent issue - it seems that the leaves look like they are getting better ... I wonder if that tiny micro nutrient (forced) deficiency was enough when compounded with slow growing to make the plant weak enough for algal attack. Interesting.

Then, < here> , we see that @tiger15 said, "Even healthy plants apparently free of algae have micro algae if examined by a microscope. "

And to what extent that algal concentration is, is likely a barometer for how "close" we are to meeting the "perfect" ratio.

With regards to an aquarium system, in agreement with Tom Barr in that concentration rather than ratios, light intensity and availability of Co2 all marry to create the potential growth capability of the plants in that system.

I am quite interested as to what is the difference between concentration rather than ratio. I am seeing ratio as relative concentrations.

Further, I think we are discussing water column concentrations, which are independent of substrate - if you use inert substrate, then your WC is a true indicator of what you have; however, we cannot say that the plant decides to use the water column over their roots at a particular moment in time - though I would love to sit down and drink coffee with Rotala to discuss the choices he/she makes.

What we can say is that higher nutrient column fertilization compounded with flow increases the probability that the plant will be able to come in contact with a nutrient - hence higher concentrations of everything "ensure" that the plant will come in contact with what it needs --- that means higher concentrations in water and/or substrate. This movement happens with concentrations (I have no link, but it must) and necessarily charges - hence too much of one HAS to inhibit something else ... leading us to relative concentrations (which is ratios).

I like what Tom said, "If you I have a ratio of 0.01 PO4 and NO3 of 0.16, I can promise you, plants will not do well," but I think it is a probability game now instead of actual nutrient availability. If you took a plant and over each leaf you had a probe with an injector that maintained this ratio NO MATTER WHAT (i.e. a response to trigger a dose when the probe reading changes) - it would have to grow as you are not limiting anything.



Back to GSA, I think we see tiny pockets of phosphate deficiency (as long as CO2 is good - remember too much phosphate increases to nutrient requirement of everything and as a result can give rise to CO2 deficiency) that GSA inhabit - why GSA ... beats me, but they must be able to uptake a particular nutrient easier than other types of algae. Why it's tiny pocket - because there aren't too many traces :p.

Please note that I have not changed my traces in my post above only potassium (which is in much higher concentration than the traces that I just suggested) and I saw a huge decrease in GSA.

These are all my thoughts and I have no evidence, but my intuition says that somewhere in here, we have a thread to why GSA and low phosphates correlate.


Josh
 
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Witcher

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9ppm NO3/6-7.5ppm PO4 weekly gives me approximately 1.5:1 to 1.2:1 NO3 : PO4 ratio with absolutely no sign of BGA, some GSA scattered here and there on older leaves of slower growing plants (and to my notes GSA appears only when my PO4 level is lowering) plus random alone hairs of green thread algae which I'm 100% sure appeared after experiments with different Fe chelates.

It's not the ratio which is important but presence of all necessary nutrients in the water column allowing plants to be fed, actively growing and producing oxygen - which I believe is most important in keeping BGA at bay.

I think in terms of ferts this topic is missing another key ingredient which is Fe (responsible for new growth and in the effect active growth of plants in general), and in terms of general environment, it's missing oxygen (or its production caused by correctly fertilised plants).
 

JoshP12

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And to what extent that algal concentration is, is likely a barometer for how "close" we are to meeting the "perfect" ratio.

I misspoke here.

What I should say that it is likely a barometer for how "close" we are to delivering nutrients via flow distribution to every single cell while at the same time NOT inhibiting nutrient uptake via obeying the "perfect" ratio - which is grounded in the unique requirements for each individual plant.

Also, the ratio itself should be expressed as a range. I cannot convince myself that:

if the toxic value for "pick your favorite nutrient" is a value t ppm, and you add t-1 ppm, that you will not have issues with plant growth. The toxic value also has to defined for each individual tank as the substrate, light, etc, all needs to be accounted for - because these are the systems ability to buffer against nutrient accumulation.

Josh
 

jaypeecee

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Hi @Geoffrey Rea
The most pertinent question I can really ask before going through with the above is has this research already been carried out? Never a point worth overlooking.

There is a huge amount of research that has been carried out on cyanobacteria, as you can imagine. But, off-hand, I know of none that have been conducted on aquaria. And, rest assured, I've looked! This is relevant as there are thousands of different species of cyanobacteria. There is one paper* that concluded "the critical Nmin-SRP mass ratios in both lakes are around 20". SRP is soluble reactive phosphorus.

But, if you already measure nitrate and phosphate in your tanks, then you've got the data that's needed. It's no big deal. @Dr Mike Oxgreen has already demonstrated, albeit on a small scale, that adjustment of N-P ratios can make a difference regarding cyano. It would be good to extend this to other hobbyists' tanks.

* https://moritz.botany.ut.ee/~olli/eutrsem/Noges08.pdf

JPC
 

Nick72

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It's interesting to see how this thread is evolving.

If I'm reading it correctly there is general agreement:

Excess of nutrients, either individual or groups, do not cause algae growth.

Having a sub optimal level of any one of the key nutrients (N,P,K,Ca,Mg,S,Fe), will lead to deficient plant growth / health and potentially cause an algae outbreak.

(Ie. The thinking behind EI)

Excess of an individual nutrient may inhibit uptake of one or more alternative nutrients causing a plant deficiency of a nutrient that is otherwise readily available in the aquarium.

(Ie. Mulder's Chart)

This makes a lot of sense to me, but the issue I have with using this information in any practical way is that Mulder's Chart does not provide any range values for nutrient levels to inhibit their counterparts.

This I assume is why we are now asking whether it is ratios between nutrients or fixed concentrations (ppm values) that trigger inhibition.

This is what I find the most interesting. Can we assign a fixed ratio or better still a fixed ppm value of a certain nutrient that will be the start of inhibition of a counterpart nutrient?

I'm suprised this research has not already taken place, or should I say I suspect the answer may he more complicated.

Perhaps nutrient X inhibits nutrient Y at 25ppm only if nutrient Z is present at >15ppm, or only if dGH is <8.

I would love to have the answers.
 

kilnakorr

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@Dr Mike Oxgreen has already demonstrated, albeit on a small scale, that adjustment of N-P ratios can make a difference regarding cyano.

I find it interesting. Not if the ratio causes BGA, but if BGA is already present, will targeting this ratio help with getting rid of it?

I'm starting to consider setting up a spare tank, and get some BGA and make it thrive outside the sweet spot and then change the ratio to see if it has any effect.
 
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Right, I now have my PO₄ test kit, and I’ve done a test.

I should highlight a couple of caveats. Firstly, I’ve only been dosing my current fert mixture (10 ppm/week NO₃ and 2.0 ppm/week PO₄) for a few days. Secondly, I am currently doing daily 25% water changes because one of my ember tetras seems to have some kind of white nodule/lesion on its lower jaw. I am, however, compensating by dosing 20% more of my fertilisers.

The PO₄ reading I've just got, interpolating between two colours, is 1.5 ppm - quite high!

I only know my NO₃ level fairly crudely from the API 5-in-1 test strips that I use, and it’s in the region of 20 ppm, or maybe a little lower. The pink colour is definitely there but incredibly faint, maybe a little fainter than the pink that indicates 20 ppm.

So if we assume that my NO₃ is somewhere between 15 to 20 ppm, that means my NO₃ : PO₄ ratio in the water column is somewhere between 10:1 to 13:1. At the moment I have no Cyanobacteria, and no appreciable amount of any other algae.

Interestingly, the blurb that comes with the test kit says that PO₄ should be 0.4 ppm or less for a freshwater tank. But they’re talking about reducing PO₄ to combat algae, which seems too simplistic.

What does seem to be the case is that I could significantly drop the PO₄ in my water column - 1.5 ppm is a lot of phosphate, and probably way more than the plants need. Which means I could probably also drop the NO₃ level as well without getting into trouble.

I wonder if I need a better NO₃ test. Which one do you use, @jaypeecee ?
 

jaypeecee

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Hi @Geoffrey Rea
It’s niche area in an aquarium is low oxygen areas with low flow.

I don't think growth of cyano necessarily correlates with low oxygen. I have had BGA/cyano growing on a filter outlet pipe where the water was turbulent because the outlet pipe was less than a centimetre from the water surface. Low flow is almost certainly relevant because of the way in which cyano gets a 'foothold' in our tanks, particularly with the filamentous cyano such as Oscillatoria, this being what I identified in one of my tanks. Exactly which species of Oscillatoria I had, I don't know.

JPC
 

jaypeecee

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Hi Folks,

It seems that some cyano are of the planktonic variety where they occupy the water column. Some, like the filamentous types, take up residence on the substrate or other surfaces. The first of these seems to be a perfect candidate for annihilation using a UV-C sterilizer. Chemical-free.

JPC
 

jaypeecee

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