Test of iron short-term overdosing on Ammania pedicellata, Cuphea anagdalloidea and other plants

deepgreen

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Hello everybody,

This started after starting to follow @Pikez Kill tank journal and noticed stunning in Ammania (Nesaea) pedicellata similar to what I had seen in my tank before. I got the impression that microferts or even iron could induce the stunning based on some observations I made over time. But impressions can be wrong, so I decided to try to overdose iron and see whether I can replicate my impressions and contribute a little bit to the puzzle of stunning in the Lythraceae. Please keep in mind that this is one trial based on the conditions in my tank.

· Tank size 90 gallons – subtracting unused space and soil approximately 300l

· Relatively high light LEDs

· Little macrofert fertilization

· RO water tip off without water changes for 2 years

· Occasional siphoning of debris with pumping back of the water

· 2 year old ADA AS with Osmocote+ root tab fertilization in some plants

· Additional occasional macro- and microfertilization

· I do not have specific doses as I adjusted it to a level that seems to work for me.

Conditions before test:

Almost no macro or microferts due to having been away for three weeks prior to the test.

I added 4 times 0.33ppm Fe2+ to the tank in 48h intervals (10ml of Flourish iron, 10.000mg/l iron)



Ammania pedicellata: Before treatment – one stem after first treatment

upload_2017-8-19_17-3-45.png

upload_2017-8-19_17-3-55.png



After 4 treatments, almost all stems were affected. However, they already seem to recover and the effect was not as strong as I have seen it before.



Cuphea anagdalloidea:

Only after treatments: Affected stem - affected and unaffected stems

upload_2017-8-19_17-4-51.png
upload_2017-8-19_17-5-3.png



Less than 20% were affected. You also see Pantanal in both images. I could not see any adverse effects on this plant. I did not see the leaf deformation in Cuphea any time before. Given that it was so conspicuous, I doubt that I missed this previously.

I did not observe any adverse effects on AR mini, AR variegated Rotala “mini butterfly”, Rotala sp “red”, Rotala macrandra, Ammania gracilis.
In fact, AR variegated changed from a dull grey to a more reddish coloration. Certainly appreciated the iron.

The day before the last treatment, my CO2 ran out leading to a high CO2 concentration as a consequence of end-of-tank-dump. Almost gassed my fish and shrimp!
Subsequently, I noticed whitening of leaves in Blyxa japonica and stunting in some stems in P. erectus. Unfortunately, I added a root tab to the erectus the day before, so I cannot really tell what affected the stunting: iron, root macros, or the CO2 spike. Four days later, the affected stems had not yet recovered.

So, what is the conclusion?

Even though this was a single test and I do not have any replicates, I would tentatively say that the iron dosing affected A. pedicellata and C. anagdalloidea UNDER my tank conditions. There is the possibility that this effect is only present together with the conditions of my tank at the time and that this kind of short-term high dosing has no effect in other tanks with different conditions. Others may have made similar observations, so this might not be novel. Nevertheless, the more we see these effects, the better is the understanding of the effects leading to stunting or growth of our plants. Therefore, I hope this little test has some value for some people.

Update 3 weeks later:
Unfortunately, the results are inconclusive. The conditions of pedicellata and anagalloidea remain the same despite no further iron dosing. The return of the greyish red in A. variegated tells me that iron should be gone. I noticed that growth of these plants more or less stopped. The test may have coincided with the depletion of my O+ root tabs which I now added again. Other plants in the tank that I provided with tabs later (E. setaceum, Syn Belem, Rio Negro Giant ...) continued to grow. It seems that a large tank where you constantly have to make changes (pruning, cleaning, fertilizing etc) is not really suited to come to a good conclusion - at least in my tank.
 
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Pikez

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Thank you, deepgreen, for that nice post.

This is helpful in that it underscores some of our collective observations. Lythraceae are sensitive to both their environment and nutrient levels, independent of light and CO2 levels. I have seen enough evidence to be unequivocal in that position.

However, the following remains an opinion: their nutrient-sensitivity seems to be related to or influenced by several environmental factors: pH? GH? KH? Sulfates? Chlorides? Sodium? Environmental toxins? The list of potential culprits is long.

The speed with which these two plants reacted no longer surprises me, as @burr740 has mentioned countless times before that he sees responses literally overnight when he changes conditions.

Granted all the standard disclaimers about multiple confounders and unique, non-replicate, single observation blah, blah, that you have to state to keep naysayers calm, you still added to our understanding of Lythraceae.

Yes, what you noticed with Ammannia pedicellata and Cuphea anagalloidea are almost identical to what I have seen under chronic over-fertilization.

It is just as interesting to note that you did not notice anything with AR, Rotalas, and A. gracilis. Of these plants, Rotala butterfly and A. gracilis, and R. sp. Red are fairly resistant to environmental conditions. They handle a wider range of conditions much better, than, say, R. wallichii, A. pedicellata, and even Cuphea.

When the conditions improve, A. pedicellata is fairly quick to recover. A. praetermissa, on the other hand, is really slow to respond to improved conditions - once stunted, it takes a while. Wallichii is quick too - the stunted tip will remain, but new un-stunted shoots will quickly sprout.

Things that I wonder about in your tank:
  • Would the effect have been different if you'd used CSM+B as your iron source?
  • Would you have noticed anything if your macros were increased proportionally?
  • Would you have noticed anything different if your water was hard and alkaline?
  • Did the Aquasoil affects the results?
  • Did the CO2 malfunction influence the results?
My educated guess would be 'yes' to all these questions above, but it'll remain a guess.

In the meantime, if you're just interested in growing these plants and not interested in science experiments, soft water + root feeding and/or soil substrate + lean water column ferts seem to consistently grow these plants well.
 

deepgreen

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These are all excellent points and I will try to respond one by one.
However, the following remains an opinion: their nutrient-sensitivity seems to be related to or influenced by several environmental factors: pH? GH? KH? Sulfates? Chlorides? Sodium? Environmental toxins? The list of potential culprits is long.
I tried to be careful in my statements. As you point out, interactions with other factors could easily change this observation. Therefore, what I observed in my tank my not happen in the tank of somebody else. This might often contribute to some controversies.

The speed with which these two plants reacted no longer surprises me, as @burr740 has mentioned countless times before that he sees responses literally overnight when he changes conditions.
Yes, what you noticed with Ammannia pedicellata and Cuphea anagalloidea are almost identical to what I have seen under chronic over-fertilization.

It is great to see such effects independently in different tanks with different conditions. May really point to iron as a major factor. But again, it is difficult to control for all these other factors.

It is just as interesting to note that you did not notice anything with AR, Rotalas, and A. gracilis. Of these plants, Rotala butterfly and A. gracilis, and R. sp. Red are fairly resistant to environmental conditions. They handle a wider range of conditions much better, than, say, R. wallichii, A. pedicellata, and even Cuphea.
It was a short peak of iron, so more permanent exposure might change the picture. Unfortunately, I do currently not have wallichii, but I try to get them just to see how they respond relative to Cuphea and pedicellata ... and they are pretty plants.

When the conditions improve, A. pedicellata is fairly quick to recover. A. praetermissa, on the other hand, is really slow to respond to improved conditions - once stunted, it takes a while. Wallichii is quick too - the stunted tip will remain, but new un-stunted shoots will quickly sprout.
At one point, I had the tips of pedicellata completely dying and this is when I became aware that something is going on. However within a week, I had side shoots. So yes, I agree that pedicellata will recover quickly. As I try with wallichii, I try to get other more sensitive plants to see whether I see correlated effects among these plants.

Quote:
Things that I wonder about in your tank:
  • Would the effect have been different if you'd used CSM+B as your iron source?
Yes, I first wanted to look at the isolated effect of iron. After everything has recovered, I plan to repeat with CSM+B. My current expectation is that the effect will be stronger based on my observations, but I need to calculate the exact iron dose in the CSM+B.
  • Would you have noticed anything if your macros were increased proportionally?
I do not know, but this is a good point. Iron might be used up more quickly leading to lower sensitivity. But I have no idea what plants do with excess iron. Do they have some storage capacity, e.g. in their vacuoles?
  • Would you have noticed anything different if your water was hard and alkaline?
I never paid attention to this because I had only a softwater tank in the last decade. I guess you are pointing towards higher iron toxicity and ph increase? I do not know the physiology behind this.
  • Did the Aquasoil affects the results?
I doubt it given that it is two years old. How many nutrients would it still release? May soil contains much organic matter as I do not regularly clean it. I even have fresh water annelids in the soil. Interesting creatures.
  • Did the CO2 malfunction influence the results?
I doubt it because I already saw the effects prior to the CO2 spike. It could have contributed in the end, though. I am still not sure about P. erectus as it does not yet show clear signs of recovery. Too many factors involved in this one.

In the meantime, if you're just interested in growing these plants and not interested in science experiments, soft water + root feeding and/or soil substrate + lean water column ferts seem to consistently grow these plants well.

I am sure they will recover to get ready for the CSM+B test. Just prior to the start of the test, I received various nice Syngonanthus from Dennis Singh. Given that they are new to my tank, I did not mention them. So far, they do well despite (or because of?) the iron peak.

I recently ordered Seachem Flourish tabs to selectively add them to some plants and see their effect in addition to the Osmocote+ tabs. The iron test told me that, besides the negative effects, at least some plants clearly benefited such as AR variegated. By using root tabs, I could potentially better adjust to the different needs of some plants.

Thanks for your exhaustive feedback.
 
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Tom Barr

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Lean water column ferts? You can grow these plants without ANY water column fertilization...........

Just soil alone.

For months, years............

I'm not clear why folks only seem interested in the high ranges.
Yes, you can taper off, but if you are curious, why do that when you can simply not add any?
That covers the entire spectrum of dosing(none to very rich).

Now, if..........you can grow the plant species in question very nicely and scape with them under both of those conditions..........what does that say?

Wallichii has done well for me easily with higher ferts, Cuphea also, and A pedicillata.
But it does well and is easier, less trouble at no ferts. None.
Just soil alone. So why not advocate that?

I would include Rotala mexicana araguaia and red types also.
Quite a few species do poorly however.

They need more NO3, K+, PO4 and traces...........
So I have dosed those at about 1/4 EI.
No issues.

Goal is not to have the plants grow so much I have to trim often for those tanks.
I also only dose once a week.

Inside, I typically dose 2x a week lately. 15 NO3, 5 PO4, 25 K+, and about 0.2 for Fe 3-5x a week.
I dropped the light on the Buce tank, does better and better. Ferts do not matter on that tank. More a light function.
Nothing new there.

120, mostly a function of CO2.
I changed some bulbs and the light shot up to about 130-140 umol on the sediment.
Did not change the CO2, got some hair algae.
Raised the light up, add more gas. Trim and do more water changes.

Realize anytime you go from low limiting levels to high levels of light or ferts.............and the gas was not CRANKED prior and AFTER the treatment(light or ferts), you run a risk of CO2 limitation.
And that invariably affects new growth and tip growth more than anything else, algae occurs later on if the CO2 limitation is strong enough.

Always keep that in mind. Ferts are easy to control, we can measure light etc, we can clean and do general maintenance and trimming. CO2............it's a pesky variable.
Still, think about a better way to test such ranges of ferts, from nothing/none, to excess. Run the spectrum of ranges. Same with light. CO2 also.

I grow nice plants, including A pedicillata in a non CO2 planted tank. No excel is added either. I dose about 1/20th EI once every 1-2 weeks.
Note, it's only about 1" wide............but it's nice and no growth issues. Just small and grows slow.
 
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deepgreen

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I agree with more or less everything you said. It depends very much on what the individual goals are. We can have gigantic plants that would naturally not occur with everything in excess and incredible growth rates. This makes the plants often more appealing for some eyes than more naturally grown ones. In addition, a tank with high water column fertilization would be probably considered a eutrophic water body in nature that will be overgrown by algae (no high CO2 naturally available) and die following the cascade of dying algae and anaerobic conditions. On the other hand, most water bodies have very little or close to none water column ferts and the plants nevertheless grow fine. So, these plants should do well in the tank without water column ferts given some in the soil. They after all come from somewhere in nature.

I also completely agree that simply growing them in ADA AS or other fertilized soil works fine. I did this with ADA AS for about 6 month with no additional ferts and just CO2 and had nice and large plants. In fact, the biggest P. erectus I ever had.

May goal is to minimize effort while maximizing good growth with healthy good-looking plants. This includes that I do not want to regularly replace the soil which is costly and quite a bit of an effort taking everything out and back again. Low effort is also the reason why I do not do water changes. Given that I use RO water, I would need to collect water the whole week and then do much pumping or draining. If I do not have time, I also sometimes just do pruning without replanting the tips. Plants will grow back while the tank will look a little rough for some time.

I am trying to push the limits with this approach: minimum number of hours per week while having a thriving diverse good-looking tank. Admittedly, there are some negative effects so far. I have algae mainly BBA that did not bother me yet as they are primarily on old stems or leaves and covered by other plants. However, seeing all these neat tanks on this forum, I will try to see whether I can control them better.

Thanks for your input.
 
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Tom Barr

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Actually where aquatic plants are present, there is no relation between nutrients and plant presence, they grow over a very wide range and grow quite well.
This is for shallow subtropical lakes, so no icing over, ample coverage of plants(30-50% or more surface coverage(Submersed). See Bachmann et al 2001.
CO2 can be limiting in some lakes, others, not that much.

So this is not a good justification really.
https://www.researchgate.net/public...indicators_and_plant_biomass_in_Florida_Lakes
 

Tom Barr

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In other words, plants define the system, not nutrients. This is a well demonstrated relationship within aquatic plant biology.
If you add more ferts, you get more weeds. If you remove the weeds, then you get pea soup.
Aquatic plant managers who kill aquatic weeds will all tell you this.
 

Tom Barr

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As far as replacing soil, you can just add a little bit of new soil every 2-3 months instead. Many add clay balls and other DIY items, but new ADA AS works very well.
You need not replace the entire sediment after 6-12 months. I don't.

I also do not do water changes in the garage tanks.


So if your goal is REALLY about less work, why add any ferts? Why fiddle so carefully and all that?
After you note the growth has slowed down some, simply add a mix of macros and traces say once a week lightly.
Or try that for say several weeks, then without any or just traces or just macros or just KNO3 etc.

Do not lose sight of the goal which is easy low labor. That little bit of ADA AS might be well worth the time you fuss with things otherwise.
You can also siphon some soil out that's getting mucked or old and add the fresh back. No need to remove it all.

Some of these picky plants are no trouble at all.
Can you squeeze a bit more out of this? Yes, adding some ferts once a week or two seems fine.
Much like the non CO2 method I use.

Still, with such a system, I can add more CMS+B and Fe and have not spotted any issues.

For my 120, I trim and garden, hardscape changes here and there etc. So water changes and more ferts are par for that.
Non CO2, I do very little, same for the tanks in the garage, they are not scaped, but I certainly could if I wanted.

70 Buce tank, very little effort also as a nature style tank.

So only one headache/higher labor trimmed tank in the house.
 
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Pikez

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Lean water column ferts? You can grow these plants without ANY water column fertilization...........

Just soil alone.

For months, years............

I'm not clear why folks only seem interested in the high ranges.
Yes, you can taper off, but if you are curious, why do that when you can simply not add any?

People are interested in high ranges for a few reasons:
  1. High ranges generally grow most plants well and fast. The key words being 'generally' and 'most.' This turns out not to be universal truth.
  2. High ranges produce better colors.
  3. High ranges eliminates possibility of deficiencies, which hobbyists are scared of.
  4. High ranges are pitched as universally consequence-free, which may not be the case.
  5. High everything - light, CO2, ferts - is in keeping with the allure and pursuit of more. Like the urge to drive a little faster when you think cops aren't around.

Now, if..........you can grow the plant species in question very nicely and scape with them under both of those conditions..........what does that say?

It says there are non-nutritional factors at play as well. We have neither identified nor defined those conditions.

There are two over-simplified and dug-in schools of thought about this:
  • 'This is trace toxicity therefore EI is flawed.'
  • 'My plants grow fine at high levels, therefore there is no problem.'
The former blame nutrients and the latter blame CO2. I think it is more complicated than that. Both of these responses, while making valid points, are missing something big or inconvenient.


Wallichii has done well for me easily with higher ferts, Cuphea also, and A pedicillata.
But it does well and is easier, less trouble at no ferts. None.
Just soil alone. So why not advocate that?

Soil and dirt are really good approaches for all Lythraceae. The best wallichii grower I know (here in LA) has them in a 300 gal dirted Discus tank with low light and low CO2. His wallachii are almost as big around as Ambulia and he grows them in hard/alkaline LA tap water. More people ought to try these simpler and slower approaches. My upcoming Kill Tank experiments will explore simpler, softer, slower and lower.

For those who just want pretty plants there are a few simple approaches to success, even if you have crappy water.
 
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deepgreen

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There are two over-simplified and dug-in schools of thought about this:
  • 'This is trace toxicity therefore EI is flawed.'
  • 'My plants grow fine at high levels, therefore there is no problem.'
The former blame nutrients and the latter blame CO2. I think it is more complicated than that. Both of these responses, while making valid points, are missing something big or inconvenient.

This is the major reason for my little test. There are obviously various approaches from simple to more demanding that range from less stunning to colorful large plants. The questions is how much can you push a simple and less demanding approach to come close to the results of the more demanding approach? What are the factors involved? I do not think that this is all already solved. One factor that has not been mentioned yet is cleanliness of the tank. Many of the successful approaches I saw here, include the meticulous removing of anything that carries algae. There are still many open questions how you can reach excellent plant growth while avoiding algae. Major factors in a high light, high fertilization tank, I can think of, are :

1. Algae inhibition through allelopathy (I think this is a major contributing factor)
2. Avoidance of algae growth by reducing algae load (removing any algae and clean tank conditions, spot treatment, only replanting healthy tips of plants ...)

My question is whether you would be as successful as you are, if you do not follow the second regime which is demanding and time consuming? Can you really have high water column fertilization with some algae load in the tank? I am not talking about low light, low growth conditions where plants do not develop their full potential. These are additional reasons why I try to play with fertilization. One side effect of the iron dosing I already observe is increased algae growth that I did not see for quite some time.
 

deepgreen

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Actually where aquatic plants are present, there is no relation between nutrients and plant presence, they grow over a very wide range and grow quite well.
This is for shallow subtropical lakes, so no icing over, ample coverage of plants(30-50% or more surface coverage(Submersed). See Bachmann et al 2001.
Good article. I guess I was referring to the hypertrophic range where high algae load had been observed in this paper. I wonder where high fertility regimes of plant tanks fall, in the eutrophic or hypertrophic range or beyond?
 

burr740

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One side effect of the iron dosing I already observe is increased algae growth that I did not see for quite some time.
This happens like clockwork in my tanks, you can set your watch by it.

Most recently I'd inched my custom micros up to .12 Fe 3x per week, up from .1 for a couple of weeks prior. GDA, which I hardly ever see, started at the .1 mark and literally exploded a few doses of .12. Not much on the plants, just the glass.

Normally by weeks end there's barely anything on the glass, even if you look from the side. Half the time doing water change maintenance I dont even wipe the glass, might do it once a month.

At .12 it didnt take 3 days before the front glass was covered. Covered enough to blur the view....after 3 days.

But like I said, very liltle that I noticed on the plants, although a few species didnt like the dose in other ways.

Long story short, went back down to .075, GDA disappeared. Plants got happy again.

GDA is normally associated with high macros, specifically NH4/ammonia, but too much Fe can trigger it too.

Disclaimer here that just because X amount is too much for my tanks doesnt mean that it's too much for everyone. That's not what Im saying at all, just sharing what happens in mine. It's certainly not too much for Tom's tank.
 
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Tom Barr

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This is the major reason for my little test. There are obviously various approaches from simple to more demanding that range from less stunning to colorful large plants. The questions is how much can you push a simple and less demanding approach to come close to the results of the more demanding approach? What are the factors involved? I do not think that this is all already solved. One factor that has not been mentioned yet is cleanliness of the tank. Many of the successful approaches I saw here, include the meticulous removing of anything that carries algae. There are still many open questions how you can reach excellent plant growth while avoiding algae. Major factors in a high light, high fertilization tank, I can think of, are :

1. Algae inhibition through allelopathy (I think this is a major contributing factor)
2. Avoidance of algae growth by reducing algae load (removing any algae and clean tank conditions, spot treatment, only replanting healthy tips of plants ...)

My question is whether you would be as successful as you are, if you do not follow the second regime which is demanding and time consuming? Can you really have high water column fertilization with some algae load in the tank? I am not talking about low light, low growth conditions where plants do not develop their full potential. These are additional reasons why I try to play with fertilization. One side effect of the iron dosing I already observe is increased algae growth that I did not see for quite some time.

Let's get back to your goal here.

1. Allelopathy is actually a very easy factor to rule out. Simply add ample amounts of activated carbon. Change every week if you want to be aggressive for say 4 weeks. That's plenty of time to remove any said allelopathic chemical inhibition and induce the algae that was otherwise suppressed/inhibited.

There, now you have a control test method.

This(AC) is what is used to test root allelopathy in plant research, so it's well understand that AC removes these compounds.
Bark up another tree. Folks have used AC for decades, there's no correlation between its usage and any algae presence.
I could add 3 of 4 other nails in the coffin for this hypothesis but the above should be clear as day for most hobbyists and easy to test themselves.

2. This is good idea no matter what but Burr, myself, others, those plants are clean as whistle without any real effort from us per se. We trim the plants well, but they really do not have much algae on them to begin with.
Sure, every screws up, they know the routine, clean, check CO2, water changes, ferts etc to get the equilibrium back after neglect.
You might add a horde of algae eating critters to #2 also, never under estimate their power.

In answering your question, frankly, I'm a bit lazy and know my habits. I will work to whip a tank back into shape that's been neglected.
Otherwise, I chose plants that tend not to need trimmed often generally, or if I have those types of faster growing weeds, I do not keep too many at once, there's a mix of slow and shorter types with the weedy species.
Hard scapes add balance and structure to over grown jungles of weedy plants. I do not need to trim wood or rock. Less work.

The picture above is a high light rich CO2 tank without any ferts added, yes, you can add a few once a week say.
But just because I have not added any ferts to the water, does not imply these tanks do not have a lot more ferts overall/total vs the plain sand/water column dosing methods.
They actually have more until perhaps 6-12 months for NH4. But even after that, they are richer in Fe and all the trace metals, PO4 etc, than most any water column routine.

My routines are sort of along the lines of ADA' but a bit richer for the dosing of the water column.
I also do not do water changes on those tanks. Like I said, I'm lazy and that's my goal with those.
But the method is easy..............and grows all the plants Burr and Pikez have troubles with. Or in other words, 95%-99% folks tend to kill or give up on.
If you are in that 1-5%, you are pretty green in the thumb.

So do not choose those plants, choose others and then plant by plant, try harder things.

Have 2 methods, Pikez is doing this, Burr is tweaking his own weird tap water.
I have a client with KCL water softening and was not told about it for a long time.
I minimize water changes, reduced the light, light water column ferts, rich CO2, ferns hold up well.

My tap at home is awesome.
But the garage tanks are lazy, my non CO2 tank, lazy, 70 Gallon Buce tank, lazy, 120 is not lazy. I keep one because of the labor factor, having 5 is nuts.
Few Dutch folks keep 4-5 dutch style tanks. Too much work.

And when the 60-90 year old guys who have done it for 40-60 years tell the young folks how to, they do not listen.
That will never change. A few will get it, many will not. But those that do not, might eventually..............if they keep after it.

My interest is more in all methods, not just a one trick pony.
No one method will be all things to all goals and to all people.
So master several methods so you can apply the best management practices for a given goal.

Pikez will likely move towards the lower light, Rich sediment type of tank, or maybe both low and high light versions.
Burr's tap limits his exploration without more headache and labor, eg, DO water or something. He justifies that well enough.
Maybe the plant Gods are punishing him? hehe
 
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Tom Barr

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Good article. I guess I was referring to the hypertrophic range where high algae load had been observed in this paper. I wonder where high fertility regimes of plant tanks fall, in the eutrophic or hypertrophic range or beyond?

Eutrophic.
 

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It says there are non-nutritional factors at play as well. We have neither identified nor defined those conditions.

There are two over-simplified and dug-in schools of thought about this:
  • 'This is trace toxicity therefore EI is flawed.'
  • 'My plants grow fine at high levels, therefore there is no problem.'
The former blame nutrients and the latter blame CO2. I think it is more complicated than that. Both of these responses, while making valid points, are missing something big or inconvenient.

Liebig's Law seems ignored even more.
Flow, good measure, timing of the CO2 delivery, Say if it's poor that 1st 1-2 hours then rich. Temperature is rarely discussed, surface scum, KH..........sediment types, clay binds much more than inert sands.
Redox and trace metals in different types of sediment. Bacteria. Algae eaters. Many folks that have issues do not have many of them

E.g. Burr and GDA, that's a non starter if you have BNP's.
If it's high nutrients, then we would HAVE to have it occur in all cases, there are dependencies. That's falsification. That falsification does not say CO2..............it just says what it is NOT.
Trace toxicity puts the cart before the horse however. It assumes that trace toxicity is the cause. EI is just a falsification of the notion that high ferts= algae. EI does not say what causes algae
I can speculate, but I've not stated what causes algae with respect to nutrients. I made some hypothesis, but they have all been falsified. CO2? Nope.

I've fixed pretty much every plant growth issue and every algae issue for my tank or another's if I'm there in person. So my speculation and fixes do work well, no one gets it 100% nor do I expect too. Certainly not on line. Too many overlooked issues and roadblocks. My failures are more art/scaping.

Soil and dirt are really good approaches for all Lythraceae. The best wallichii grower I know (here in LA) has them in a 300 gal dirted Discus tank with low light and low CO2. His wallachii are almost as big around as Ambulia and he grows them in hard/alkaline LA tap water. More people ought to try these simpler and slower approaches. My upcoming Kill Tank experiments will explore simpler, softer, slower and lower.

For those who just want pretty plants there are a few simple approaches to success, even if you have crappy water.

I'm familiar with LA water. Not as bad as Santa Barbara or Davis tap water. Not even 1/2 as bad.
Still, if you do few or stop water changes, have the soil, that will purify the tank's water even if crap.
Or salt like KCL.........

So you should give this a go next. I think you will like the results.
But that's just my speculation............
 

deepgreen

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Let's get back to your goal here.

1. Allelopathy is actually a very easy factor to rule out. Simply add ample amounts of activated carbon. Change every week if you want to be aggressive for say 4 weeks. That's plenty of time to remove any said allelopathic chemical inhibition and induce the algae that was otherwise suppressed/inhibited.
...
Bark up another tree. Folks have used AC for decades, there's no correlation between its usage and any algae presence.

I think there are plenty of rigorous studies that demonstrated allelopathy in some aquatic plants for green microalgae or cyonabacteria e.g.Wu et al 2007 and subsequent referring papers.
https://link.springer.com/article/10.1007/s10750-007-0787-2

Whether this can be replicated under the conditions of a plant tank, I do not know. There can be several factors involved such as size of the AC filter, local effect of the plants ... I often see algae growth on the stem, or roots and not leaves. Why do we have such differences? I think there are still many factors we do not understand about plant defenses against algae.

Furthermore, I do not think we can really pin down what factor exactly leads to the absence of algae in some tanks.
Burr observed the increase in algae with microferts increase, I did so as well. This does not mean high microferts = high algae growth. You demonstrated repeatedly that it does not happen in your tanks. Obviously, we are missing something here.

The little iron test, though obviously not meeting any scientific standards, still gives me some idea how individual factors can lead to specific effects, simply I change A and B responds in a specific way. You did probably do this many times with your tanks. But still, can anybody precisely explain why algae do not appear in some tanks while they do in others?

I do not think it is a single factor but the interaction of multiple factor which makes it so difficult to really explain it and which leads to so many opinions about it. Tank conditions vary between people, so they are obviously not comparable and then there are the opinions "but this is what I see in my tank".

It is great to have these exchanges of opinions while understanding that conditions in tanks vary. You obviously have decades of experience and you pointed out many potential routes which would probably keep me busy for years ;). I will try and see what I can adapt. Probably only the "lazy" approaches :)

For now, I will probably first wait until everything is stable again. As Pikez just pointed out in his Kill tank journal, patience is important.
 

Tom Barr

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You can cite something that shows it in a natural aquatic system...........I'm all ears. Just a lab filtrate test.
You NEED to see the methods. Did they do water changes? Do you?
Did they do reverse removal, eg, after they had run the test, post treatment remove the allelopathic compounds?
These are classic herbicide and algicide methods.
Why? Because you can be lured into a false conclusion.

Same deal with the backing off of dosing after any sign of initial algae.
You need to see if it continues.

Many hobbyists do NOT, why? Because they are less curious and more just trying and often struggling to have an algae free tank.
Many had that when I suggested dosing more PO4.

SOME got algae, but with increased plant growth, they needed more CO2.
Strongly limiting traces, likely what is happening there, does and certainly CAN limit growth, alleavating CO2 demand and other nutrients.
Liebig's law, not an opinion, predicts this.
It predicted it with PO4 limitation as well.

Allelopathy:
How do you provide a control for a natural aquatic macrophyte system to test this?
No one has done this to date.
Test wells, lab and bench scale stuff.
We need field test.

How does a plant "know" how big the water volume is?
How do all 400-500 plants all produce a similar suppression for algae? Do they all make the same allelopathic chemicals at the same amount?
What about unidirectional aquatic system like Rivers? The chemicals are swept away immediately.

Have you used Activated carbon to test your claim here?
I'm guessing no. It is a standard method for any allelopathic research.
If you can show adding AC cause algae, I'm all ears and would be surprised.
No one is over 30 years have shown any correlation there.
But the thing is, being a standard method, and being easy and available..........it is easy to try.
Note, also removes Chelated Fe.

Ole Peterson also had a harsh review of allelopathy in planted aquariums.
http://www.bio-web.dk/ole_pedersen/pdf/tag_2002_15_7.pdf

My questions, suggestions and critique differs from his.


You see algae on older plant organs, not new growth(if so, the algae is rampant throughout the tank).
Takes time to have algae colonize.

Algae is on most all plants, noxious algae, not so much. Diatoms are typical for most well run tanks if you take a leaf out and look at it under a scope.

I can consistently manage algae in a planted tank. So while there might be many causes for algae, this is more a human issue rather than one of some nefarious evil algae trying to gain the upper hand.
I have no issues with algae management. It's more a sign of neglect and poor horticulture.
You whip the tank back into shape and it is done.

I would suggest you NOT waste your time on allelopathy, nor would Ole.
I would focus on trying non CO2 methods, soil based systems, rich CO2 in others, good general care.

Like Bart said at the talk on Dutch Aquariums, after 60 years in the hobby, the new people do not want to listen to the old Judges coming to their home to judge their tanks, they want to learn the hard way.
I get it. I tend to approach things more observational. Then think about testing my hypothesis. What methods would I use? Statistics? Variation between treatments? What can I reasonable rule out as a potential cause?
Note, this is rarely if ever a single test. It's several test trying to find a cause by ruling the other hypothesis out. Deduction.

I do not think of a conclusion, then go back and look for evidence to support it.
If I had a nickel every time a planted aquarist fell for that approach...........

It took me 3 years to figure out BBA, took Amano 10 years. Today, most can avoid it and fix it fast.
Things are better.

FYI, the non CO2 methods I suggest have a very high rate of success and less algae than the CO2 methods.
Something to ponder.
 
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deepgreen

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I appreciate your advice and I understand that there are ways to limit algae growth in various tank settings. But I would also like to better understand the causal background of limiting algae growth.

It is well established that most plants grow well when given all nutrients in excess. This is known since Liebig invented the nitrogen fertilizer which you repeatedly pointed out. The major question that remains, however, is what prevents algae from growing in tanks with high levels of ferts. They are also plants or cyanobacteria and the same rules should apply to them. The competition with higher plants argument does not work here because your fertilization regime prevents exactly that. You provide everything in excess so algae should have them at ad libitum as well. Still, you do not have them in your high fert tanks. You and others repeatedly demonstrated THAT it works but it is still unclear WHY it works. So far, I did not yet see a satisfactory causal explanation for this. I do not yet buy that there is no direct or indirect effects on algae growth through plants in the tanks whether it is allelopathy or some other effect. Negative results are always problematic because there is always the possibility that something was missing in the experiment. Given that it is difficult to show an inhibiting direct or indirect effect of plants on algae growth in plant tanks, one can reverse the problem and take the factor “higher plants” away. I would like to see that a tank with your high fertilization regime does NOT develop algae when the plants are taken away. Obviously, there should be some compensation for the lacking nutrition uptake by plants. However, this should be manageable. If you can demonstrate the absence of algae growth under these conditions, then I buy that plants are not involved, directly or indirectly, in inhibiting algae growth.
 
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deepgreen

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Update 3 weeks later:
Unfortunately, the results are inconclusive. The conditions of pedicellata and anagalloidea remain the same despite no further iron dosing. The return of the greyish red in A. variegated tells me that iron should be gone. I noticed that growth of these plants more or less stopped. The test may have coincided with the depletion of my O+ root tabs which I now added again. Other plants in the tank that I provided with tabs later (E. setaceum, Syn Belem, Rio Negro Giant ...) continued to grow. It seems that a large tank where you constantly have to make changes (pruning, cleaning, fertilizing etc) is not really suited to come to a good conclusions - at least in my tank. More controlled conditions would definitely help.