Lean dosing pros and cons

[plantnoobdude]

I shared these before, not sure if everyone have seen this but for the benefit of those who haven't. while it's not a journal, tons of pics!
Happi-singh

 

[ElleDee]

@Simon Cole, you are giving me flashbacks to my master's defense here, but if you are doing things properly I don't believe you have multiple replications within the same tank because the tank itself is the experimental unit. It's is the smallest grouping that could be randomly assigned to a treatment, so to have replication you have to have more tanks, not sample more within the tank. Everything in one tank belongs to the same treatment, so it's all one unit. If you took multiple measurements of plants within the tank they could be treated as subsamples if the data were pooled, or if you compared different species it could be treated as a separate experiment.

(I learned about this using apple trees as an example - you can't create reps by sampling more apples from the same two trees and comparing apples. The entire tree gets the same treatment, so you have to compare entire trees. Everything treatment you add requires multiple additional trees and that's why the apple program takes up so much space on the research farm.)

This is very off in the weeds of experimental design, but it comes up a lot in the plant sciences. I understand we aren't trying to publish a journal article here, but I just want to recognize some of what it takes to do even straightforward research.

 

[John q]

I will just very politely suggest that unless we are in on this thread ready to play along, have an open-mind and are ready to dispense with a bit of disbelief and are actually interested in possibly trying out the lean approach

Well said mate 👏

For me, I was incredibly sceptical at the start of this thread way back in November, but think I've shown I'm willing to try alternative approaches to see "if" it works.

I don't have picturesque tanks with difficult plants for our members to gaze upon in awe. I also don't have a wife that would allow me to set up several test tanks, although I constantly try and push the boundaries 😅

What I can offer is 2 tanks, with fish and lots of plants, and a simplistic approach of dosing certain fertiliser regimes and reporting my findings.

I've no axe to grind, my knowledge is lacking, and I'm here to learn... that last sentence probably sums up 99% of the peeps that visit ukaps.

With that in mind let's all play nice 🥴

 

[Simon Cole]

I don't believe you have multiple replications within the same tank because the tank itself is the experimental unit... so to have replication you have to have more tanks

Very good point.
Suppose we wanted to test the impact of carbon dioxide enrichment on 100 terrestrial pine trees. We would have one field planted with trees maintained in enriched conditions, and we would have another with ambient carbon dioxide levels. In an ideal world, we would have numerous fields replicating the study, but we have to rely upon other researchers to replicate the experiment. Sure if we had enough fields that could account for experimental failures (like the enrichment system failing to provide enough nutrients and for variation between fields), but is that really necessary. Is it reasonable and is it possible. Experimental research always suffers from this kind of criticism. If there is belief afterwards that the experiment did not account for an unknown variable then there is the option of Bayesian statistics afterwards, and if something was missed that it can be investigated in the future. Few experiments are designed perfectly. But it is often still possible to add a drop to the knowledge pool.

I would have scolded your assessors if they did not have legitimate belief for an unknown variable affecting your Master's project. That is why it is better to discuss experiments in advance and agree the terms of reference. If they told me that an experiment was not possible on just two fields, then I would turn around and ask them to prove it. Let them try refuting a conjecture with absence of evidence. If they could show me that the carbon dioxide enrichment system has a 50% chance of breaking, then I would agree that this risk was not factored. But if they had no data, then my evidence is valid and their conjecture is an imaginary bias.

So taking the example of an aquarium, if the two tanks had statistically significant results in plant growth after the experiment was repeated... and then it was found that the temperature on one was slightly higher. That would mean that the next experiment would have to show that that temperature difference was a valid variable. Both tanks would be planted and have identical conditions except for temperature... so on and so forth. To me, it doesn't matter whether you have one tank of a hundred, if you are testing two populations of cloned planted with defined variables and controlled conditions then you will be able to draw enough evidence for me to believe it.

Too many unknowns?
I have no idea. But in order for there to be too many unknowns, it must either be demonstrated scientifically or there must be belief.
I don't know whether I'm that bothered personally. In a practical sense there will always be too many unknowns. But at least we would know the value of different dosing strategies. And when I say value, it might be insignificant. I was going to study dung beetles at one point. That is relatively more insignificant, or is it, I don't know. But at least I would salute anyone for trying to resolve these issues.
We actually need certificates of scientific achievement. The UKAPS Nobel prize award.

 

[dw1305]

Hi all,

....... but if you are doing things properly I don't believe you have multiple replications within the same tank because the tank itself is the experimental unit. It's is the smallest grouping that could be randomly assigned to a treatment, so to have replication you have to have more tanks, not sample more within the tank.

That one for me. The question then becomes "how small in volume can the tanks be?" Before that invalidates the DOE.

Experimental research always suffers from this kind of criticism. If there is belief afterwards that the experiment did not account for an unknown variable then there is the option of Bayesian statistics afterwards, and if something was missed that it can be investigated in the future. Few experiments are designed perfectly. But it is often still possible to add a drop to the knowledge pool.

That <"is also true">. I think the only way you could really do this is by <"metadata analysis">.

cheers Darrel

 

[GreggZ]

So taking the example of an aquarium, if the two tanks had statistically significant results in plant growth after the experiment was repeated... and then it was found that the temperature on one was slightly higher. That would mean that the next experiment would have to show that that temperature difference was a valid variable. Both tanks would be planted and have identical conditions except for temperature... so on and so forth.

This is exactly why it's so difficult to pinpoint any absolute truths in this hobby. Someone performs an "experiment" then deems that "proof". The only thing it proved it was happened in that tank with those exact set of parameters.

I have personally done all kinds of experiments with my tank over the years. I've also documented the results. Does it have value? Maybe anecdotally.

Here's the thing. Even given all that I have observed over many years, half the time I could very well be drawing the wrong conclusions. This hobby is far from an exact science that is for sure!!

 

[plantnoobdude]

This is exactly why it's so difficult to pinpoint any absolute truths in this hobby. Someone performs an "experiment" then deems that "proof". The only thing it proved it was happened in that tank with those exact set of parameters.

yep, this goes for most everything in the hobby. I'll link it back to what Vin coined conditional tolerance/intolerance. lets say I add 4ppm K weekly instead of the 1.3ppm K I am dosing now. and my ammannia stunts, can I say that ammannia stunts under high K? no. I can only say that under my tank conditions, increasing levels of K causes problems in ammannia. it is very hard to conclusively prove anything about plants in aquariums, because there are just too many variables.

 

[ElleDee]

Very good point.
Suppose we wanted to test the impact of carbon dioxide enrichment on 100 terrestrial pine trees. We would have one field planted with trees maintained in enriched conditions, and we would have another with ambient carbon dioxide levels. In an ideal world, we would have numerous fields replicating the study, but we have to rely upon other researchers to replicate the experiment. Sure if we had enough fields that could account for experimental failures (like the enrichment system failing to provide enough nutrients and for variation between fields), but is that really necessary. Is it reasonable and is it possible. Experimental research always suffers from this kind of criticism. If there is belief afterwards that the experiment did not account for an unknown variable then there is the option of Bayesian statistics afterwards, and if something was missed that it can be investigated in the future. Few experiments are designed perfectly. But it is often still possible to add a drop to the knowledge pool.

I would have scolded your assessors if they did not have legitimate belief for an unknown variable affecting your Master's project. That is why it is better to discuss experiments in advance and agree the terms of reference. If they told me that an experiment was not possible on just two fields, then I would turn around and ask them to prove it. Let them try refuting a conjecture with absence of evidence. If they could show me that the carbon dioxide enrichment system has a 50% chance of breaking, then I would agree that this risk was not factored. But if they had no data, then my evidence is valid and their conjecture is an imaginary bias.

So taking the example of an aquarium, if the two tanks had statistically significant results in plant growth after the experiment was repeated... and then it was found that the temperature on one was slightly higher. That would mean that the next experiment would have to show that that temperature difference was a valid variable. Both tanks would be planted and have identical conditions except for temperature... so on and so forth. To me, it doesn't matter whether you have one tank of a hundred, if you are testing two populations of cloned planted with defined variables and controlled conditions then you will be able to draw enough evidence for me to believe it.

It is necessary, reasonable, and possible. It is standard practice for agricultural experiments! First, you can usually divide fields into individual plots that receive the treatments (randomly assigned to control for within-field variation) so the experimental unit is not the entire field and it is quite common to have the whole experiment run in several different fields and always, always over multiple years. If you're lucky you may have other research partners to help, but that's not always the case. It is an enormous pain to be sure, but it's done that way for a mathematical reason, not conjecture.

I don't know anything about how other types of research is done, but the design for these kinds of plant/field experiments is pretty well established and not routinely criticized. Probably every student has a moment where they are like, "Ughhhh, why do I have to do this much work anyway????" but by the end of my program I had learned how the statistics work, and in many cases I was required to read the foundational papers on which the practices were based. The concept of pseudoreplication, which is what we were talking about with the tank being the experimental unit, goes back to this paper from 1986, but a lot of the ins and outs of experimental design were pioneered in the 1950s and 60s. Nobody is making extra work for no reason, and in fact a lot of effort has gone into figuring out the minimum amount of work needed to move the science forward.

But to address the last bit, it is assumed that there is going to be variation within the experiment that you can't control for no matter what, be it temperature or what else. If you conduct the same experiment twice, even if you try to get it perfect, you are going to end up with results that are different. You hope that they are not that different, but you don't know how it's going to turn out until you do it, in part because you don't know the answer to the question you are research ahead of time. This is why replication and randomization is so important - they work to distribute all the little differences (aka experimental error) more or less evenly between treatment groups and without it you can end up with very, very wrong conclusions.

That one for me. The question then becomes "how small in volume can the tanks be?" Before that invalidates the DOE.

That <"is also true">. I think the only way you could really do this is by <"metadata analysis">.

It's a good question that I don't really know the answer to. Well, the answer is that it can be as small as you want so long as the size of the tank is not itself influencing the growth of the plant so much that you wouldn't be able to generalize the results of the experiment, but I don't know what that is. You might be able to go pretty small, but obviously it'd have to be uniform and the tanks would have to be randomized in space (can't have all the tanks from one treatment grouped together). I definitely haven't thought through how best to control for error in this sort of experiment.

As for metadata analysis, that's a weaksauce desperation move for when you can't do proper randomized, controlled experiments. That's sort of a joke, but one of the joys of a plant experiment is that we can work with literal clones that we have total control over. This is why we can get away with just 6 or so replications per treatment instead of the sometimes thousands of subjects needed for human research. It's quite a bargain if you look at it that way!

 

[GreggZ]

yep, this goes for most everything in the hobby. I'll link it back to what Vin coined conditional tolerance/intolerance. lets say I add 4ppm K weekly instead of the 1.3ppm K I am dosing now. and my ammannia stunts, can I say that ammannia stunts under high K? no. I can only say that under my tank conditions, increasing levels of K causes problems in ammannia. it is very hard to conclusively prove anything about plants in aquariums, because there are just too many variables.

Exactly. I was talking with Vin about this just the other day. Most would be surprised how humble many of the well known folks in the hobby are about their conclusions. Part of that may be over time they've seen it all and understand how easy it is to make false assumptions in this hobby.

That's why it's difficult to let some of the broad proclamations of fact in this thread go unchecked. They are stated as facts, but they are in fact opinion. They claim to be backed up with science, but the experiments only reflect an isolated result observed in those specific parameters. Many times it has little correlation to actual results that hobbyists experience.

 

[Guest]

Sorry late to the party and don’t have time to read the entire thread. Just out of interest did anyone actually come up with a definition of lean dosing?

 

[aquanoobie]

Hi all
Macek.g presented tons of beatiful pictures and as a bonus he included info on dosing. Thank you macek!

Let's see

NO3 7.2 ppm per week or 1 ppm a day
NO3 10 ppm per week or 1.4 ppm a day
7 ppm NO3 from KNO3 and 5 NO3 from urea per week or 1 ppm and 0.7 ppm a day

P04 0.2 - 0.5 ppm per week or 0.03 - 0.07 ppm a day

K 12 ppm per week or 1.7 ppm a day
K 8 - 15 ppm per week or 1.1 ppm and 2.1 ppm a day

Everybody agrees macek's and his friend's tanks are super beautiful. And he also disclosed the dosing strategy. Isn't this an opportunity to establish what lean means? Because if this is lean then we have nothing to argue about. It works wonders the proof is here. We don't need million dollar scientific research to prove it, just open your eyes.

Macek also mentioned light at 120 PAR.

This thread has now more than thousand posts but it wasn't necessary because the title is "Lean dosing pros and cons". It doesn't say "Lean versus rich dosing", it doesn't say "Rich dosing pros". I didn't want to criticize but at the same time I see people are noticing it too.

Thank you all

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[MichaelJ]

Just out of interest did anyone actually come up with a definition of lean dosing?

Wait!, what?

But seriously Tim, I don't really think anyone completely carved it out in stone yet. 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

There might be more, but thats what I have picked up so far.

And of course, regardless of our choice of water and dosing we still have to make sure we have stable water parameters, adequate filtration and flow and keep our maintenance up to par - the lean regime might enable us to do WC's less frequent but of course also depends on factors such as stocking levels vs. plant mass etc. Less than weekly WC's is not my objective though.

Cheers,
Michael

 

[plantnoobdude]

Wait!, what?

But seriously Tim, I don't really think anyone completely carved it out in stone yet. 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

There might be more, but thats what I have picked up so far.

And of course, regardless of our choice of water and dosing we still have to make sure we have stable water parameters, adequate filtration and flow and keep our maintenance up to par - the lean regime might enable us to do WC's less frequent but of course also depends on factors such as stocking levels vs. plant mass etc. Less than weekly WC's is not my objective though.

Cheers,
Michael

as for wc's I have gone two weeks since my last water change. the day after the water change, tds was 120. today, two weeks later the tds is 121ppm. I top off with ro to a set point every few days. (line on side of the tank). logically, I could go much longer without water changes, but i still want to change water atleast every two weeks for now, I will be swapping to 25% twice a month for now.

 

[Zeus.]

• Rich/mature substrate
• Weekly low (lean) amounts of NPK with N primarily from NH4/Urea/NH4NO3

Sounds a bit like the ADA system - substrate packed with nutrients and ferts at low levels 😉

I like the idea of the experiment, however in practice it would be hard/costly having controls and ideally you shouldn't now which tank was getting say EI level ferts , low level ferts and no ferts and would take some time. Would need multiple tanks at least three for each sample IMO ( We could still say its single blind as plants don't have eyes )

 

[MichaelJ]

as for wc's I have gone two weeks since my last water change. the day after the water change, tds was 120. today, two weeks later the tds is 121ppm. I top off with ro to a set point every few days. (line on side of the tank). logically, I could go much longer without water changes, but i still want to change water atleast every two weeks for now, I will be swapping to 25% twice a month for now.

HI @plantnoobdude I will definitely monitor TDS - as I've done weekly for a long time now - If I eventually don't see much reason to keep up the weekly WC's I will try and put it off for another week or just do less weekly. Also as a side-note I have removed most of my floating plants in my lean tank to avoid too much carnage from having them sucking up all the fertilizers (sorry Darrel/@dw1305 I had to do it lol) and to let more light in 🙂 ... I still have the stems floating but I hope to put them into the substrate tomorrow and post a picture. Half the tank is still a jungle and the other half was completely weeded out to give rooom for the more challenging stems. Its completely messed up, but I am not in it to win any prices or admiration from aquascapers

Cheers,
Michael

 

[MichaelJ]

Sounds a bit like the ADA system - substrate packed with nutrients and ferts at low levels 😉

Hi @Zeus. I'll have to read up on the ADA system ... so my substrate is actually regular gravel, but it's very mature (+2 years old), so I would suggest it's packed with lots of microbial activity and nutrients - which brings up the question of the sustainability when/if the substrate gets "depleted" - I'm not too worried though.

I like the idea of the experiment, however in practice it would be hard/costly having controls and ideally you shouldn't now which tank was getting say EI level ferts , low level ferts and no ferts and would take some time. Would need multiple tanks at least three for each sample IMO ( We could still say its single blind as plants don't have eyes )

Right on. Would be hard, very time consuming and very costly to run these experiments with all it takes to make it meet the rigorous protocol you would normally expect from a bonafide scientific experiment.

Cheers,
Michael

 

[GreggZ]

as for wc's I have gone two weeks since my last water change. the day after the water change, tds was 120. today, two weeks later the tds is 121ppm. I top off with ro to a set point every few days. (line on side of the tank). logically, I could go much longer without water changes, but i still want to change water atleast every two weeks for now, I will be swapping to 25% twice a month for now.

Not a judgement on water changes, but a TDS meter is a good gauge of nutrients in the system but not dissolved organics and waste.

 

[JoshP12]

Sorry late to the party and don’t have time to read the entire thread. Just out of interest did anyone actually come up with a definition of lean dosing?

i love it.

The irony is the plant doesn’t care. It grows.

Lean is a fallacy. So is rich. You can give millions of ppm but what’s in the plant under any given condition?

It’s intuitive.

We have 2 mediums for nutrition:
1) water column
2) substrate

Lean substrate = inert

Rich substrate = high CEC with “natural” (poop) or “artificial” enrichment (root tabs)

Medium substrate = inert with tabs

Medium substrate is not so good. With low CEC things get messy. CEC = cation exchange capacity

The root can choose what nutrients it takes. Put simply: Amazonia should fry anything in it with that ammonia … it doesn’t - clearly the root is a master chooser or has an anti-ammonia super power and anti-phosphorous or something lol.

So just go rich substrate it will help. And like that’s really rich. Super rich. Thousands of ppm rich. Put that in water and everything die.

Back to 1) —> water column
Dosing often refers to N/P since and here I go again - the nutrient pathway at leaf interface for Nitrogen and Phosphate is unregulated in the same way that the rest are and N and P get forced into the leaf and have to be used.

To define rich, we have to create a datum, a relative beast.
So lean = no N and P
Medium = some N and and P
Rich = more N and P

Needs numbers? Medium = PPS pro Rich = EI Lean = less

But get this, PPS pro is pretty darn rich — it forces plants to grow. And get this ADA high K drives growth via leidbig and forces the rich substrate to top up the nutrients … so ADA IS RICH!!!!!

it’s all fake. It’s not real. There is no lean. There is no rich.

Plant needs nutrient to grow. It will grow based on what you feed it and like Darrel always says like a car assembly and it will just grow.

The concept of Rich vs Lean has to do with how much N and P you force feed (I cheated by saying ADA leveraged N and P demand via leidbig and potassium - because it does —- but through our definition of rich, it is lean since low N and P in column).

The plant grows based on what it can get inside it. What you put in is not magical and it is not rich or lean - it is. And the plant acquires it and tops itself up from the root - and if it can adapt it will.

On the adaptation note - if you want to predict whether a plant will grow well under rich conditions, then compare it’s submerged form to its emersed form … notice Anubias looks the same (grows fine under EI and poor co2 implementation <—- see that … all plants can grow under EI with good co2 and good light and good gas …) … Pogostemon erectus looks kinda similar … grows fine under decent co2 and EI … Rotala looks completely different lol <— struggles under EI with poor substrate and co2 — in the same conditions Anubias will grow fine.

This has to do with the ability for N and P to regulate metabolic rates and influence co2 demand - there is no way around it.

Yep … it’s intuitive.

And after 1000 of these posts, I think a reader will have the intuition … or rage quit and buy commercial fertilizer, lights, and soil and follow the instructions enjoying their hobby in peace 😂.

 

[erwin123]

Rotala looks completely different lol <— struggles under EI with poor substrate and co2 — in the same conditions Anubias will grow fine.

sweeping statements like "Rotala struggles under EI with poor substrate and Co2" may lead to unnecessary controversy. Best to be more specific - for example, if you had problems growing Rotala using EI, you can share your experience, but there are others who have no problem with EI and inert substrate who may be willing to share how to do it.

 

[MichaelJ]

Yep … it’s intuitive.

Hi @JoshP12 I like your posts, and they are interesting to try and decipher, but often I am never entirely sure what some of you posts means to be honest - No offense, your writing style is probably just too dense - dense; as in "too closely compacted in terms of substance" for me to comprehend 🙂

Cheers,
Michael