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Maq's experiment 23b

John q said:
For us simple folks what would be an ideal Mn mg/l ratio to Fe. Is the 1.5 to 2.5 ratio in mg/l relevant, if not how does the simple lay person work this out.
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An ideal ratio Fe:Mn can be deduced from Marschner - it's 2:1 (both weight and molar because atomic weights are very close).
Andy Pierce said:
I don't believe the ratios of nutrient X to nutrient Y matter - just the levels of X and Y. Excessive Mn is toxic sure, but you're not going to overcome that toxicity by increasing the levels of Ca, Mg, Fe and/or P.
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I'm not sure whether I can fully understand what you mean. I'll stick to manganese:
(a) Uptake of manganese by plants can be influenced by Fe and Mg. They are in a competitive relationship.
(b) Accessibility (or toxicity) of manganese may be influenced by many variables, but if we stick to nutrients, we can name iron and phosphorus. Manganese forms insoluble compounds with phosphorus and adsorbs on iron compounds. Such a manganese is non-toxic, but also not directly accessible to plants.
An example: Consider tank A. I've dosed the same amount of iron as in tanks C and D. And severe chlorosis quickly developed only in tank A. Why? Primarily due to high level of phosphate. You can see it with your own eyes. Ratios do matter.
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Back to @John q 's question: Marschner provides an ideal ratio, but when dosing these two nutrients, we must take into consideration assumed losses. These losses depend on some variables, and are not identical for Fe and Mn. The nearest to the ideal are conditions of acidic, very soft water with lean dosing.
That is, roughly speaking, my long-term goal. Not to overdose, not to waste, keep all nutrients as low as possible to avoid competition and excessive losses due to precipitation.
 
_Maq_ said:
I've dosed the same amount of iron as in tanks C and D. And severe chlorosis quickly developed only in tank A. Why? Primarily due to high level of phosphate. You can see it with your own eyes. Ratios do matter.
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Let me rephrase my original statement: I don't believe the ratios of soluble nutrient X to soluble nutrient Y matter. In other words, I don't believe the biochemistry. (I'd like to read Marschner; is that available other than behind a paywall?) I do, however, believe in the inorganic chemistry, for example the precipitation of iron by phosphate, or indeed the formation of plant-unusable manganese oxides - 'Manganese Dynamics in Soil'. It is to avoid inorganic precipitation that mostly you hear of people fertilising with chelated iron, and not with free iron salts, as well as the concept of dosing macronutrients and micronutrients on alternating days with EI ferts, or at least not putting the macros and micros in the same concentrated stock solution bottle. The other reason to use chelated iron is that algae cannot directly use chelated iron whereas with free iron ions in the water column the algae have a great chance at outcompeting the other plants. I love your 23B experiment, but dosing FeCl3 would not be my choice for how to fertilise with iron.
 
@Andy Pierce

I believe the Idea behind Maq's experiment is to make sure all the nutrients are easily available in the water Colum. you are likely to see precipitations and other flaws caused by unfavorable ratios and excess nutrients in these tests. "Ratios do play an important role"

far as Algae is concerned, both plant and algae will have equal opportunities to use the nutrients from the water, especially if those nutrients are easily available. the higher the nutrients, the stronger the algae will appear, the lower the nutrients, the less the algae will appear. when Maq originally setup this experiment, I predicted which tank will have less algae based on the Nutrients level alone #82
 
 
Andy Pierce said:
I don't believe the ratios of soluble nutrient X to soluble nutrient Y matter.
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I'm only currently exploring this myself, but I absolutely believe that ratios are important for at least certain plant species. In the 'targeting potassium' thread, I made a comment with pictures of my experience with ratios correcting a long-standing issue - Targeting Potassium

I had warped growth on hygrophilia siamensis 53b. CO2 was at max the fish could tolerate, with 2 yellow drop checkers. I had tried dosing even greater amounts than EI. The only thing that worked, was to reduce my potassium dosing to 5ppm. I think it's unlikely that there is a 'golden ratio' that will work for every single plant species, but I definitely now believe that plants have preferences for certain ratios. I suspect this may be even more relevant for water column dosing, and that nutritious substrates like aqua soils may be able to overcome incorrect balances. Although the latter part is mainly just a theory since I haven't tested it yet.
 
The final redpill : Lean dosing is the goal for healthy, algae free and colorfull plant, some get there at first, some like me need to go though EI and find someone that deliver the redpill =)

Incredible topic, thanks so much
 
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_Maq_ said:
An example: Consider tank A. I've dosed the same amount of iron as in tanks C and D. And severe chlorosis quickly developed only in tank A. Why? Primarily due to high level of phosphate. You can see it with your own eyes. Ratios do matter.
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We can see the image, but where and how was it concluded it was primarily because of high (5ppm) phosphate?
Based on your posts here we can count 8 water parameters with different values between tanks A and C and D (pH, conductivity, K, NH4, HCO3, H2PO4, OH, NO3 ). Was it the PO4 level or the 10 to 27x higher OH dosed in tank A? Or the additional 27x higher HCO3? A pH above 7 (tank A) can’t be great for non-chelatated iron... a ph of around 6(C and D) might be better even with high PO4. Besides iron itself, there are 5 different known dosed parameters and 3 different known measured levels ... at least 16 known unknowns as current nutrient concentrations in the 3 tanks and many unknown unknowns because as you put it :
_Maq_ said:
Yes. Each of the tanks has got a different history prior to this test. So, algae, par example, must be compared to initial state.
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In my opinion singling out phosphate based on the current observations has no grounds. The logical leaps, appeal to senses to conclude that ratios do matter than seem underhanded.[/b]
 
Andy Pierce said:
This is not the case. Plants' ability to utilise EDTA-chelated iron
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I do not contest the notion that using Fe-chelates can increase Fe uptake by plants. But plants take up iron in ionic form, i.e. unchelated. They do not uptake Fe-EDTA. Just like the algae.
 
Ria95 said:
In my opinion singling out phosphate based on the current observations has no grounds.
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I think we are rather somewhere in between "has no grounds" and "it's proven". Yes, beside phosphates, bicarbonates and pH too have great influence on iron uptake. And quite possibly some other variables can be at play.
I've stressed several times that I don't take the results for "proof"; rather for "suggestion, indication". There's always a risk of wrong interpretation of indices. But I'm running various tests for a while, already, and intend to go on. Step after step, my/our assumptions shall be getting firmer grounds.
 
_Maq_ said:
I think we are rather somewhere in between "has no grounds" and "it's proven".
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That‘s good news. What are the grounds on which in tank A vs C/D phosphate was singled out as the reason for loss of available iron? As opposed to say bicarbonate or OH?

_Maq_ said:
I've stressed several times that I don't take the results for "proof"; rather for "suggestion, indication". There's always a risk of wrong interpretation of indices.
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I remember you saying something to that effect. In light of that, how would the conclusion of the previously quoted post ‘Ratios do matter.‘ look like if we apply the same uncertainty?
 
Day 24:
A. measuring,
B. water change.

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Interesting development in tanks A and B. I didn't anticipate such a strong decrease of pH value. In any case, it may be an interesting contribution to discussions on these topics:
(a) that nitrification gets very weak below pH = 6, and
(b) that big filters with huge colonization area media are necessary to support efficient nitrification.

At the same time, I've observed the signs of iron deficiency in tank A receding. This probably supports @Ria95 's assessment that not phosphates but rather high pH and bicarbonate content were the main reasons of iron deficiency.

I proceed to water change 50 %.
 
Ria95 said:
In light of that, how would the conclusion of the previously quoted post ‘Ratios do matter.‘ look like if we apply the same uncertainty?
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I welcome your criticism, it's stimulating.
My assessment that high phosphates hinder iron uptake is not based solely on this experiment. Precipitation of FePO4 is well documented in environmental literature. Also, many hobbyists have observed brownish powder on the bottoms of their canister filters. Reversely, iron oxides are used to remove phosphates from water.
In fact, I'm permanently adjusting my dosing of phosphates and iron to avoid losses and insufficiency of either of them. Most of my tanks are firmly in acidic realm, and yet multiple times I've observed issues with both of them which likely were attributable to their interactions.
 
_Maq_ said:
high pH and bicarbonate content were the main reasons of iron deficiency.
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this was expected to happen, especially when Iron is not chelated. I believe some of us already had the concern about the PH and HCO3 from very beginning. I wish you could eliminate all the CO3 on all these setups. are you able to try the DTPA Iron, sometime down the road?
 
_Maq_ said:
I welcome your criticism, it's stimulating.
My assessment that high phosphates hinder iron uptake is not based solely on this experiment. Precipitation of FePO4 is well documented in environmental literature. Also, many hobbyists have observed brownish powder on the bottoms of their canister filters. Reversely, iron oxides are used to remove phosphates from water.
In fact, I'm permanently adjusting my dosing of phosphates and iron to avoid losses and insufficiency of either of them. Most of my tanks are firmly in acidic realm, and yet multiple times I've observed issues with both of them which likely were attributable to their interactions.
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Precipitation of Fe and PO4 was present when Fe gluconate and PO4 were present in the same solution, even when the solution was acidic. it was observed that this Precipitation occurred within few hours and it was more noticeable as the day went by. I would picture the same to occur in the aquarium.
 
Happi said:
are you able to try the DTPA Iron, sometime down the road?
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I have EDTA. I could prepare Na-Fe-EDTA. In fact, I did, a while ago. It didn't work for me any better than FeCl3, so I've abandoned it.

After 24 days, I have to admit that this experiment lacks focus. I've attempted to try too many variables. I apologize to all observers. Still, I believe it can deliver some useful information. I'm not going to terminate it prematurely. But you, please, try to take it just as a mere one article in a chain of experiments which contribute to knowing the unknown.
 
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