• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up
  • You can now follow UKAPS on Instagram.

Lean dosing pros and cons

GreggZ

Member
Joined
4 Mar 2022
Messages
239
Location
Novi, MI 48374
Indeed it does and that's a fact. Tap water can contains a good amount of CO2 due to how the water is processed in water plants before it is sent back into the pipes. This is not intentional but a consequence of the water treatment processes.
Agreed. Tap water can contain a good deal of CO2. The same for well water. I've got well water going through an RO system, and even after the RO the water still contains CO2.

Many people make the mistake of testing pH right out the tap. It's always best to fully degas and age it for a few days. And it can cut both ways.

Sometimes there is CO2 added which lowers pH, and there can also be other things (like sodium hydroxide) added that raise pH. Either way best to let a sample to come to equilibrium with atmosphere before testing.
 

Alexv95

New Member
Joined
11 Sep 2020
Messages
18
Location
France
I'm back a little late but the conversation still seems relevant.

I think that's pretty much the nub of it. Aquatic plants adapted to life under water will be pretty good at absorbing gases from the atmosphere. So when they're exposed to 410ppm CO2, as opposed to 10ppm in water, via a daily water change you bet they're going to do okay, so no great mystery.

And I'm guessing they'll most likely store atmospheric gases in their aerenchyma to be used later on in the photoperiod upon re-submergence. This method of getting CO2 in to aquatic plants is nothing new I remember reading about it way back, not sure where, probably the Barr Report.

Thank you I was not aware of this possibility. I did have in mind the possibility of adding CO2 via tap water.
To know if the CO2 contribution comes from the new water or from the atmosphere, I think a test could be done with a false water change: empty the tank and fill it with the same water from the tank. If the plants grow well / better with this false water change, this would indicate that the capture of CO2 from the air is effective for their growth.

wow.. these are really beautiful. Plants look really vibrant and healthy, significantly better than any of my non-CO2 supplemented softwater tanks. However, I am little bit confused as I see Amazon link for CO2 kit in most of his video descriptions. Are you absolutely sure that these are non-CO2 setups?
With the pictures I think your tanks are better. Have you ever tried to stop changing the water in your tanks? With the lean dosing it seems that it could work but there is still the question of CO2 input with these water changes.
 

Tim Harrison

Administrator
UKAPS Team
Joined
5 Nov 2011
Messages
9,045
Location
UK
I think a test could be done with a false water change: empty the tank and fill it with the same water from the tank.
That’d be one way of doing it. If you leave tap water to degas in a container overnight it’d be pretty safe to assume CO2 levels would equilibrate with atmospheric levels.
 

Sudipta

Member
Joined
3 Mar 2022
Messages
56
Location
Minnesota
With the pictures I think your tanks are better. Have you ever tried to stop changing the water in your tanks?
Although I have not done this with any of my non-CO2 supplemented softwater tanks but I have been experimenting with Ammannia pedicillata golden in a small plastic container. It has been almost 4 months since I have done any water change and I also added huge amount of ammonia containing root tab but the plants are still doing okay (top leaves are getting smaller since I posted the last update on June 20.)
We can't directly correlate this with actual planted tank but I still think it is somewhat informative.
Here is the link;
 

_Maq_

Member
Joined
23 Jun 2022
Messages
365
Location
Czech Republic
Plants
I disagree. Marschner's numbers are valid universally. Only monocots require much less Ca.
However, plants differ significantly in their abilities to uptake nutrients upon differing external conditions, par example pH.
Mostly, not exclusively. But yes, uptake of other forms is of minor significance, perhaps with the exception of P.
  • For micro-nutrients the three levels are <"none", "some" and "toxic">. As long as we are in the "some" zone nothing else really matters.
To that I'd add that toxic levels are difficult to detect. I suspect toxicity of micronutrients happens more often than we believe.
Fertilisers
I suggest that a community called UKAPS should adopt strictly negative attitude toward commercial blends of nutrients, aka "universal" fertilizers. Nothing of that sort can ever exist. It may be a way for beginners or less engaged hobbyists, but a forum dedicated to aquatic plants should be aware of its inherent limitations.
Just out of interest did anyone actually come up with a definition of lean dosing?
In natural habitats, P and N (less often) are usually limiting nutrients. Plants are adapted to that. My experience strongly suggests that if these two are in short supply, plants grow slowly but signs of nutritional imbalance seldom appear. On the other hand, if N or P are plentiful and any other nutrient is not in adequate supply, plants show signs of nutrient deficiencies.
So I suggest we stick to N & P when talking about "rich" or "lean". To me, lean dosing is close to what plants know from their natural habitats. I define it not by its content in water column (P is difficult to measure, and most of it is in the substrate, anyway; ammonium also tends to get adsorbed to organic matter in the substrate) but by the content in the water I use for water change.
Usually, I change 20 per cent water weekly, and that water contains 1 to 3 µM P (0.1 to 0.3 mg/L H3PO4) and 16 to 48 µM N (equivalent to 1 to 3 mg/L NO3). The actual amount available to plants is supposedly lower because of plant and microbial consumption. In any case, it is still more than in most natural habitats. Keeping these levels, my plants do not stunt and rarely show nutrient deficiencies, but they grow relatively slowly.
Can we call it "lean dosing"?
I can only vaguely attempt to define it myself - but I think the prerequisites goes something like this:
  • Soft to very soft water (almost complete absence of KH and very low GH (2-4 GH).
  • Slightly acidic to acidic water (High 6 to down to high 5 pH)
  • Rich/mature substrate
  • Weekly low (lean) amounts of NPK with N primarily from NH4/Urea/NH4NO3 and with an eye for ratios (Marschner).
  • Low amount of traces, but carefully crafted/picked in terms of choice of elements and chelates.
  • Low'ish temperature
Although soft and acidic waters are typically low-nutrient in the nature, I don't see good enough reasons for tying lean conditions exclusively with them. Like I said, it's the content (or, more precisely, availability) of N & P which defines "lean" and "rich".
I'm hesitant when reading words "nutrient-rich substrate". A very clean silica sand is relatively "passive" substrate, meaning its sorption ability is low. However, once it gets enriched with decaying organic matter (detritus), adsorption increases significantly. From then on, individual nutrients behave in their own natural ways. Nitrates, chlorides, sulfates, molybdates do not adsorb, so they do not accumulate in the substrate. Ammonium, sodium, potassium, magnesium, calcium, and boron adsorb on clays, if present, in differing degree (subject to the type of clay and ambient factors like pH), and partially on detritus. Phosphorus and transition metals tend to desert water column rapidly both because of microbial uptake and adsorption.
I've experimented with enriching substrate with purified clays, zeolites, ferric oxide, charcoal, and peat. None of them is a source of nutrients per se, they just enhance adsorption of selected nutrients. In theory, keeping nutrients within the substrate should be a good anti-algae measure, and some reports confirm that it may work in natural waters. My experiments did not lead to any remarkable results, so the question remains open to me.
Enriching sediment with fertilizers in pills/tabs? Many aquarists report good results. It depends. If they release nutrients too quickly, microbes (not plants) will be the first to gain advantage and proliferate. With that, some negative development may occur. I don't use them.
@dw1305: EI (rich dosing) obviously works, although I still don't fully understand why.
Neither do I! Plants should be stressed from high concentrations of nutrients. Microbes should flood the tank. Phytoplanton should quickly dominate and suppress macrophytes by light attenuation. Yet it does not happen. Why?
My only suggestion (pretty weak) is that plants massively supported by CO2 produce in excess secondary metabolites incl. those which may have an allelopathic effect.
If you are using KNO3 and not Urea, then it is not lean. The K is too high in relation to N, so it's not lean. If you were not using the correct recipe for micros, then it is not lean.
Excess K is not a problem in relation to N & P, but in relation to Mg, Ca (and Na). The latter happens pretty often, it's perhaps the most widespread source of nutritional defects.
Micros cannot be effectively measured. Yes, I follow Marschner when preparing my stock solutions; it's a good measure not to overdose. But then, I follow what the plants tell me. Iron deficiency occurs most often by far. Those who use tap water should know that tap water very often contains more than enough micronutrients. Again, with the exception of iron.
My approach is similar to tropica or Marchner as already mentioned before. Weekly target of:
N 3 (containing 50-75% urea/nh4 components)
P 0.3
K 2-3
Fe 0.1
Traces similar to tropica or somewhere between tropica and tenso cocktail, mainly maintaining Fe:Mn ratio at 2:1
Gh 2-3, kh 0-1 is sufficient, adding higher GH 5 or so with 0-1 kh give you better option of adding more Fe and Micros. Higher GH also create an mechanism that protect plants from being harmed in case of overdosing of micros.
Adding more K 5-10 under higher GH will also work fine, it might not be needed in such quantities.
Marschner is a good starting point, yet it cannot be followed in practice. Firstly, plants uptake some nutrients preferentially in relation to others. Typically, K vs. Mg & Ca, or P vs. S. Secondly, in many cases the question of availability is decisive. So it's not bad to dose Fe and Mn in 2:1 ratio, but in the end, you have to observe your plants and detect the signs of deficiency.
I would never suggest dosing micronutrients on regular basis, without plants' feedback, and most of all, I find outright dangerous to use commercial blends of micronutrients. They are made for farmers. Conditions in fields differ substantially from those in our tanks. The main difference is that in the field many micros are lost due to leaching, but in a tank, transition metals accumulate! Typically, Tenso Coctail is rich in molybdenum, because Mo (unlike other transition metals) poorly binds to soil particles, and much is lost due leaching. Another difference is that in fields, oxic conditions prevail. The presence of oxygen is decisive in making micros (and phosphorus) soluble or insoluble.
 

_Maq_

Member
Joined
23 Jun 2022
Messages
365
Location
Czech Republic
In spring, I tested Ammannia crassicaulis and Ludwigia glandulosa. In broad terms, tanks A and B (from left to right) were acidic, tanks C and D were alkaline. Tanks A & C featured lean dosing (16 µM N), tanks B & D rich dosing (160 µM N).
You can see that both plants were able to utilize increased doses of N & P. Thus, they don't belong among the group of slow-growers. (Slow-growers are generally unable to benefit from increased available nutrients, so, in nature, they are outcompeted in fertile biotopes. On the other hand, they invest in durability of their tissues, so they can "wait", while "fast-growers" cannot cope with nutrient-limited conditions. Roughly speaking - for details, ask @Simon Cole).😆
Secondly, you can see that Ludwigias stunted in C & D. All tanks were freshly established and in all of them, I took pain to dose all micronutrients in the very same amount. Ammanias prospered both in acidic and alkaline conditions, but Ludwigias were unable to uptake micros in alkaline water. So, increased dosing of micros was of no use if the given species cannot manage. (More detailed pics and mineral composition of water can be submitted if anyone interested.)

ABCD(75).png
 

erwin123

Member
Joined
4 Mar 2021
Messages
953
Location
Singapore
Thats an interesting photo, thanks for sharing. 2 observations:

While C & D appear to have slower growth, the red colour of the Ludwigia glandulosa in C& D appears to be more attractive.
Ammannia crassicaulis didn't turn red under lean dosing and remained very green
 

_Maq_

Member
Joined
23 Jun 2022
Messages
365
Location
Czech Republic
the red colour of the Ludwigia glandulosa in C& D appears to be more attractive
It looks nice but it's due to lack of chlorophyll. So it's a defect.
Most likely, my plants were genuine Ammannia crassicaulis. Most A. c. in the trade are actually Ammannia gracilis which takes orange-reddish hue much more easily. In my experience, A. crassicaulis remains yellow even under intense light. But yes, under high-tech high-light high-all treatment things may turn differently.
 

dw1305

Expert
UKAPS Team
Joined
7 Apr 2008
Messages
13,988
Location
nr Bath
Hi all,
I disagree. Marschner's numbers are valid universally.
You may well be right.

This is the Third Edition of <"Marschner’s Mineral Nutrition of Higher Plants">. Personally <"I'm not after optimal growth"> etc., I just want some plant growth.
I suggest that a community called UKAPS should adopt strictly negative attitude toward commercial blends of nutrients, aka "universal" fertilizers. Nothing of that sort can ever exist. It may be a way for beginners or less engaged hobbyists, but a forum dedicated to aquatic plants should be aware of its inherent limitations.
I can see where you are coming from, and many of our members do use dry salts, but I think it is a <"bit of a stretch"> to expect people to buy all the individual salts to make up their own <"micro-nutrient mixes"> etc. and I'd guess that even the people who do make their own mixes are going to use a commercial <"trace element mix">.

There are inherent limitations of <"commercial fertiliser mixes">, but there is also the disclaimer that commercial hydroponic fertilisers must fulfill the basic requirement of promoting plant growth, or they companies that make them would have gone out of business.

I'm going to stick by what I wrote earlier in the thread, and I'm going to carry on recommending <"Solufeed 2 : 1 : 4"> etc.
Plants
Fertilisers
cheers Darrel
 
Last edited:

GreggZ

Member
Joined
4 Mar 2022
Messages
239
Location
Novi, MI 48374
In spring, I tested Ammannia crassicaulis and Ludwigia glandulosa. In broad terms, tanks A and B (from left to right) were acidic, tanks C and D were alkaline. Tanks A & C featured lean dosing (16 µM N), tanks B & D rich dosing (160 µM N).
You can see that both plants were able to utilize increased doses of N & P. Thus, they don't belong among the group of slow-growers. (Slow-growers are generally unable to benefit from increased available nutrients, so, in nature, they are outcompeted in fertile biotopes. On the other hand, they invest in durability of their tissues, so they can "wait", while "fast-growers" cannot cope with nutrient-limited conditions. Roughly speaking - for details, ask @Simon Cole).😆
Secondly, you can see that Ludwigias stunted in C & D. All tanks were freshly established and in all of them, I took pain to dose all micronutrients in the very same amount. Ammanias prospered both in acidic and alkaline conditions, but Ludwigias were unable to uptake micros in alkaline water. So, increased dosing of micros was of no use if the given species cannot manage. (More detailed pics and mineral composition of water can be submitted if anyone interested.)

View attachment 191296
While I find the results interesting in a very general broad sense, IMO it does not really “prove” much at all.

The problem with these types of experiments is that it doesn’t account for the many other variables from tank to tank. Pretty much what this proves is what happened in those particular tanks, with that particular set up, and those particular plants.

Let’s say we add CO2, or vary the concentration of CO2, how do plants react? Let’s say we provide a fresh nutrient rich substrate, what happens? Increase light? Decrease light? Increase water changes? Decrease water changes. Add fish? Increase dGH? Decrease dGH? Change dGH Ca/Mg ratio? Vacuum substrate regularly, never vacuum substrate? Add more micros? Add less micros? Vary macro nutrient composition and ratios? More PO4, less PO4? Add more K? Less K?

And I could go on and on.

In the real world with a real tank all these variables are at play every day. Each tank is a unique ecosystem. And not to be lost is that different plants have different optimal conditions. You may set up a tank to grow something like Rotala Wallachii perfectly, but when you add 20 other species you will realize that they may have different preferences.

What I find far more interesting is someone who can keep a wide variety of plants at near peak health and create something beautiful. And I do understand that is not your focus. But even so the plants in these tanks do not look to be in peak health. Lot’s of algae on old growth and the substrate looks dirty with algae as well.

I think sometimes folks make the mistake of looking at a tank like a science experiment. In my experience it’s part science and part art. Heck even something as underdiscussed as pruning/horticulture skills can make the difference between success and failure. A technique that works with one plant might cause another to fail. The only way to learn these things is with time and experience.

Heck I have planted the same plant in three different spots in my tank and two flourish and one fails? All seemingly in the same conditions. Just saying the mysteries of the planted tank are not easily solved like a math problem. And of all the things that make for a great planted tank, nutrient dosing is probably the least important. A well run planted tank can get by well on a wide range of nutrients and a nutrient centric approach many times leads to failure. People can’t see the forest through the trees.

Funny thing is that when you get to know some of the best in the hobby not once does the discussion of Marschner's ratio come up. In fact dosing is pretty low on the list of what is discussed.
 

dw1305

Expert
UKAPS Team
Joined
7 Apr 2008
Messages
13,988
Location
nr Bath
Hi all,
In natural habitats, P and N (less often) are usually limiting nutrients. Plants are adapted to that. My experience strongly suggests that if these two are in short supply, plants grow slowly but signs of nutritional imbalance seldom appear. On the other hand, if N or P are plentiful and any other nutrient is not in adequate supply, plants show signs of nutrient deficiencies.
I'm pretty sure that is right.
A very clean silica sand is relatively "passive" substrate, meaning its sorption ability is low. However, once it gets enriched with decaying organic matter (detritus), adsorption increases significantly. From then on, individual nutrients behave in their own natural ways. Nitrates, chlorides, sulfates, molybdates do not adsorb, so they do not accumulate in the substrate. Ammonium, sodium, potassium, magnesium, calcium, and boron adsorb on clays, if present, in differing degree (subject to the type of clay and ambient factors like pH), and partially on detritus. Phosphorus and transition metals tend to desert water column rapidly both because of microbial uptake and adsorption.
I've experimented with enriching substrate with purified clays, zeolites, ferric oxide, charcoal, and peat. None of them is a source of nutrients per se, they just enhance adsorption of selected nutrients. In theory, keeping nutrients within the substrate should be a good anti-algae measure, and some reports confirm that it may work in natural waters. My experiments did not lead to any remarkable results, so the question remains open to me.
Enriching sediment with fertilizers in pills/tabs? Many aquarists report good results. It depends. If they release nutrients too quickly, microbes (not plants) will be the first to gain advantage and proliferate.
That is also basically where I'm coming from. I've been using "lean dosing" with a ~90% silica sand substrate with a small addition of Oak (Quercus) or Beech (Fagus) leaf mold and neutral clay <"for a long time now">.
Micros cannot be effectively measured. Yes, I follow Marschner when preparing my stock solutions; it's a good measure not to overdose. But then, I follow what the plants tell me. Iron deficiency occurs most often by far. Those who use tap water should know that tap water very often contains more than enough micronutrients. Again, with the exception of iron
Agreed, I don't think there is any point in trying to measure micro-nutrient levels in the tank, I'm also much keener on "watching the plants", and it is a <"scientifically valid"> method. It doesn't work <"particularly well for iron (Fe)">, which is, as you say, a <"common, and easy to recognise, micro-nutrient deficiency">.
In the real world with a real tank all these variables are at play every day. Each tank is a unique ecosystem. And not to be lost is that different plants have different optimal conditions. You may set up a tank to grow something like Rotala Wallachii perfectly, but when you add 20 other species you will realize that they may have different preferences.
You can see that both plants were able to utilize increased doses of N & P. Thus, they don't belong among the group of slow-growers. (Slow-growers are generally unable to benefit from increased available nutrients, so, in nature, they are outcompeted in fertile biotopes. On the other hand, they invest in durability of their tissues, so they can "wait", while "fast-growers" cannot cope with nutrient-limited conditions. Roughly speaking - for details, ask @Simon Cole).
Agreed as well, it is the <"horses for courses"> argument. I've framed it in terms that you wouldn't try and grow <"Orchids and Tomatoes"> in exactly the same growing conditions, so why <"should all aquarium plants be the same">?
I think sometimes folks make the mistake of looking at a tank like a science experiment. In my experience it’s part science and part art. Heck even something as underdiscussed as pruning/horticulture skills can make the difference between success and failure. A technique that works with one plant might cause another to fail. The only way to learn these things is with time and experience.
Same for me, a <"shades of grey world">. Personally I'm <"reasonably good with plants">, but <"I'm still cr*p with fish">. I've got better, but <"from a very low starting point">.
And of all the things that make for a great planted tank, nutrient dosing is probably the least important. A well run planted tank can get by well on a wide range of nutrients and a nutrient centric approach many times leads to failure. People can’t see the forest through the trees.

Funny thing is that when you get to know some of the best in the hobby not once does the discussion of Marschner's ratio come up. In fact dosing is pretty low on the list of what is discussed.
Same for me again.

cheers Darrel
 
Last edited:

erwin123

Member
Joined
4 Mar 2021
Messages
953
Location
Singapore
Funny thing is that when you get to know some of the best in the hobby not once does the discussion of Marschner's ratio come up. In fact dosing is pretty low on the list of what is discussed.

I do not have a chemistry/plant biology background, so I am happy to keep it simple.

For someone like myself, it seems to make sense to buy a bottle of ferts off the shelf and dose the tank with it. At roughly 1 ml a day, my 500ml bottle will last me more than 1 year.
 

dw1305

Expert
UKAPS Team
Joined
7 Apr 2008
Messages
13,988
Location
nr Bath
Hi all,
For someone like myself, it seems to make sense to buy a bottle of ferts off the shelf and dose the tank with it. At roughly 1 ml a day, my 500ml bottle will last me more than 1 year.
I guess that is it, if people can buy an easy to use, off the shelf solution that works they will, and why not?

Personally I'm much too mean to give my money to the participants in the <"World's most expensive water"> competition, but I'm also much too lazy to actually make up my own fertiliser any more, when there is a <"cheap, and acceptable, compromise"*>.

* I realise that it won't be an acceptable compromise for every-one.

cheers Darrel
 

GreggZ

Member
Joined
4 Mar 2022
Messages
239
Location
Novi, MI 48374
I do not have a chemistry/plant biology background, so I am happy to keep it simple.

For someone like myself, it seems to make sense to buy a bottle of ferts off the shelf and dose the tank with it. At roughly 1 ml a day, my 500ml bottle will last me more than 1 year.
This is exactly why Xiaozhuang Wong sells thousands of bottles of APT Complete. The vast majority have no idea what is in it or the level of nutrients it provides. And they don't want to. Most of the world has very small tanks and it's a matter of convenience.

We have to keep in mind that nuts like us (including myself!) on forums like this are the exception not the rule.
 

_Maq_

Member
Joined
23 Jun 2022
Messages
365
Location
Czech Republic
I'd guess that even the people who do make their own mixes are going to use a commercial <"trace element mix">
I think it depends on whether you believe in necessity to use chelates.
The problem with these types of experiments is that it doesn’t account for the many other variables from tank to tank. Pretty much what this proves is what happened in those particular tanks, with that particular set up, and those particular plants.
The way to reveal step by step the significance of individual variables in relation to the whole is doing precisely this kind of experiments. I took care to keep as many as possible variables identical in all four tanks and make them differ in two parameters only: acidic vs. alkaline and lean vs. rich. I've demonstrated that both species are able to benefit from rich nutrition, and only one of them is well adapted to alkaline environment.
And not to be lost is that different plants have different optimal conditions.
But that was exactly what made me to make the test - to demonstrate different responses to external conditions by two species.
But even so the plants in these tanks do not look to be in peak health. Lot’s of algae on old growth and the substrate looks dirty with algae as well.
I agree. Only that what you see is mostly fungi, most likely, because they appeared during dark cycling. However, you seem to fail to understand what experiments are performed for. It is not to take some plants and gradually adjust conditions to a state when they look (unnaturally) perfect. It is to expose them to chosen conditions and then observe, describe, and discuss the results. If algae appear, then be it. If the plants outright die, then be it. That's what experiments work like.
But frankly, I've seldom seen Ludwigia glandulosa in better shape (in tank A), even in CO2 enriched tanks. Perhaps more detailed photos would show, but, interestingly, you did not show interest.
I think sometimes folks make the mistake of looking at a tank like a science experiment.
I think sometimes folks make the mistake of looking at a tank designed for simple scientific experiments by judging it by their personal approach to the hobby.
I fully understand that most hobbyists will ever be just hobbyists and never perform experiments. But to dismiss them, par example with an argument that one experiment cannot solve the whole truth in its full complexity, is just wrong. My tests are not truly "scientific", but in broader terms, this is how the science is made. Step by step, always with limited (and disputable) results, yet always pushing the limits of our knowledge a bit further.
Some invent/create new cars, and many many more just drive them. Ignorance is fully permissible, but some people still must create new, better cars.
Funny thing is that when you get to know some of the best in the hobby not once does the discussion of Marschner's ratio come up. In fact dosing is pretty low on the list of what is discussed.
Who are some of the best? I suppose they are those who are eminent in what you consider the result. Believe or not, I'm tired and actually don't like high-tech gardens which are so adored by general public. When it comes to aesthetic value, they are mostly kitch, a popular art. When it comes to learning the nature, they are outright the opposite because their methods and goals are unnatural.
I'm not about to fight a war to change this state of affairs. I'm just trying to explain that your approach is not the only possible.
That said, I'll be the first to stress over and over that care for plants does not begin with mineralization/fertilization. Does it mean we should not investigate the influence of nutrition?
 

KirstyF

Member
Joined
25 Jul 2021
Messages
493
Location
Kidderminster
I think it depends on whether you believe in necessity to use chelates.

The way to reveal step by step the significance of individual variables in relation to the whole is doing precisely this kind of experiments. I took care to keep as many as possible variables identical in all four tanks and make them differ in two parameters only: acidic vs. alkaline and lean vs. rich. I've demonstrated that both species are able to benefit from rich nutrition, and only one of them is well adapted to alkaline environment.

But that was exactly what made me to make the test - to demonstrate different responses to external conditions by two species.

I agree. Only that what you see is mostly fungi, most likely, because they appeared during dark cycling. However, you seem to fail to understand what experiments are performed for. It is not to take some plants and gradually adjust conditions to a state when they look (unnaturally) perfect. It is to expose them to chosen conditions and then observe, describe, and discuss the results. If algae appear, then be it. If the plants outright die, then be it. That's what experiments work like.
But frankly, I've seldom seen Ludwigia glandulosa in better shape (in tank A), even in CO2 enriched tanks. Perhaps more detailed photos would show, but, interestingly, you did not show interest.

I think sometimes folks make the mistake of looking at a tank designed for simple scientific experiments by judging it by their personal approach to the hobby.
I fully understand that most hobbyists will ever be just hobbyists and never perform experiments. But to dismiss them, par example with an argument that one experiment cannot solve the whole truth in its full complexity, is just wrong. My tests are not truly "scientific", but in broader terms, this is how the science is made. Step by step, always with limited (and disputable) results, yet always pushing the limits of our knowledge a bit further.
Some invent/create new cars, and many many more just drive them. Ignorance is fully permissible, but some people still must create new, better cars.

Who are some of the best? I suppose they are those who are eminent in what you consider the result. Believe or not, I'm tired and actually don't like high-tech gardens which are so adored by general public. When it comes to aesthetic value, they are mostly kitch, a popular art. When it comes to learning the nature, they are outright the opposite because their methods and goals are unnatural.
I'm not about to fight a war to change this state of affairs. I'm just trying to explain that your approach is not the only possible.
That said, I'll be the first to stress over and over that care for plants does not begin with mineralization/fertilization. Does it mean we should not investigate the influence of nutrition?

I’d have to say, I couldn’t agree with @_Maq_ more. Anything that has the potential to expand knowledge even a little bit and even when not fully conclusive (after all, what in this hobby is) is a worthy cause.

Tom Barr presumably ran experiments to establish the nutritional parameters around EI and whether you agree with him or not in regard to the benefits of such, he has contributed to the hobby.

Tom Barr also advises on any number of other elements of aquatic husbandry, including a holistic approach, but EI, in itself, is still a ferts regime.

As a hard water user, I certainly found Maq’s post interesting and it probably raises more questions for me than it answers, but that can only be a good thing and a motivation for further enquiry……and I’d take a guess and say I still don’t have as many questions as he’s still asking himself!
 

Alexv95

New Member
Joined
11 Sep 2020
Messages
18
Location
France
Ludwigias were unable to uptake micros in alkaline water. So, increased dosing of micros was of no use if the given species cannot manage. (More detailed pics and mineral composition of water can be submitted if anyone interested.)

View attachment 191296
Thanks you for sharing. I am interested in more details: how much micro (iron) do you dose? How often? What chelator was used? Wouldn't using a different chelator (with better alkaline water stability) have solved the micro absorption problem?
In relation to alkalinity, are you talking about Ca, Mg or HCO3-?
I find these experiments very interesting but like @GreggZ , I think it is important to keep in mind the limitations and not to think that the conclusions are universal and that it will be impossible to grow this plant in an alkaline environment (I'm sure you know this but not necessarily all readers do).

Although I have not done this with any of my non-CO2 supplemented softwater tanks but I have been experimenting with Ammannia pedicillata golden in a small plastic container. It has been almost 4 months since I have done any water change and I also added huge amount of ammonia containing root tab but the plants are still doing okay (top leaves are getting smaller since I posted the last update on June 20.)
We can't directly correlate this with actual planted tank but I still think it is somewhat informative.
Here is the link;
Tank you, yes I've already found and bookmark your topic, it's very useful.

Marschner is a good starting point, yet it cannot be followed in practice. Firstly, plants uptake some nutrients preferentially in relation to others. Typically, K vs. Mg & Ca, or P vs. S. Secondly, in many cases the question of availability is decisive. So it's not bad to dose Fe and Mn in 2:1 ratio, but in the end, you have to observe your plants and detect the signs of deficiency.
I'd be interested to know how you do it in practice (but it's probably too long to summarise it here). In my modest experience, I found it very difficult and I have often encountered similar problems in visual appearance but with different causes.
 

_Maq_

Member
Joined
23 Jun 2022
Messages
365
Location
Czech Republic
I am interested in more details: how much micro (iron) do you dose? How often? What chelator was used?
I think I'll start a new thread (or share this information in my Introduction thread). This is rather complex issue and a bit off-topic, here.
Wouldn't using a different chelator (with better alkaline water stability) have solved the micro absorption problem?
Possibly. But I rather think not. Let me believe that Ludwigia glandulosa cannot live in pH > 7.0, unless somebody proves otherwise.
In relation to alkalinity, are you talking about Ca, Mg or HCO3-?
I use the term 'hardness' when referring to Mg & Ca content.
'Alkalinity' stands for more precise acid neutralizing capacity. When I refer to pH, I use terms 'acidic' and 'basic'. But 'alkaline' is perhaps permissible, too. Yet I'll be happy if any of present native speakers corrects my terminology.
I think it is important to keep in mind the limitations and not to think that the conclusions are universal and that it will be impossible to grow this plant in an alkaline environment (I'm sure you know this but not necessarily all readers do).
I don't believe that Ludwigia glandulosa can live in basic/alkaline environment. But I'm open to demonstration that I'm wrong.
(There's a real distinction between pH over 7, and high content of bicarbonates. Both have rather distinct implications in plant metabolism. My test did not reveal whether the core of the problem is higher pH or bicarbonates. In that, I'll happily see someone to test it.)
I'd be interested to know how you do it in practice (but it's probably too long to summarise it here). In my modest experience, I found it very difficult and I have often encountered similar problems in visual appearance but with different causes.
I'm no magician. Yet I can tell you that keeping simultaneously the same species in differing physico-chemical environments helps a lot.
micurin-22a.png
 

Freshflora

New Member
Joined
20 Apr 2022
Messages
18
Location
Los Angeles, CA, US
I think I'll start a new thread (or share this information in my Introduction thread). This is rather complex issue and a bit off-topic, here.

Possibly. But I rather think not. Let me believe that Ludwigia glandulosa cannot live in pH > 7.0, unless somebody proves otherwise.

I use the term 'hardness' when referring to Mg & Ca content.
'Alkalinity' stands for more precise acid neutralizing capacity. When I refer to pH, I use terms 'acidic' and 'basic'. But 'alkaline' is perhaps permissible, too. Yet I'll be happy if any of present native speakers corrects my terminology.

I don't believe that Ludwigia glandulosa can live in basic/alkaline environment. But I'm open to demonstration that I'm wrong.
(There's a real distinction between pH over 7, and high content of bicarbonates. Both have rather distinct implications in plant metabolism. My test did not reveal whether the core of the problem is higher pH or bicarbonates. In that, I'll happily see someone to test it.)

I'm no magician. Yet I can tell you that keeping simultaneously the same species in differing physico-chemical environments helps a lot.
View attachment 191311
Ludwigia glandulosa/peruensis can definitely be grown/live in alkaline and hard conditions. I’m guessing a KH of 11 and a GH of 14 is hard and alkaline enough to demonstrate that? Those are this guy’s conditions. He grew it for an extended period of time in those parameters and pretty healthily. Tsing's 125 Hybrid - IAPLC 2020 - Rank 840.
 

_Maq_

Member
Joined
23 Jun 2022
Messages
365
Location
Czech Republic
Thank you. @Freshflora
I'm curious to what degree strongly chelated micronutrients can help overcome limitations given by nature. It seems this is one of such instances.
 
Top