Nutrient levels and plant growth represented on a chart for most planted tanks.

[Tug]

Could this chart represent all of the factors affecting growth rate in planted tanks? From what I've been able to gather there is a generally large range for nutrients that provide non-limiting nutrients for max growth. To me, it seems to cover most planted tank situations. Any thoughts?

 

[Solcielo lawrencia]

One graph can't include all factors. For example, temperature, nutrients, flow, etc.

 

[Tom Barr]

One graph can't include all factors. For example, temperature, nutrients, flow, etc.

Agreed.


Many have tried, but I see more issues with being rigid with all the factors. They are linked, but it gets messy as you include 3 or more variables.


2 is okay, Ole and Troels did this with CO2 and light for a single plant without roots, Riccia.


They had 9 treatments.


If you added 3 levels of ferts, then you'd have 27 treatments.


Then the matrix is a mess.


My tanks all have higher CO2 than the graph for example, while someone with a canister filter might be unable to do that.


That is just 1 example.


Then when it comes to measuring things, IME, most aquarist are woefully bad at it. And even if not, they often make assumptions that lead to poor conclusions.


I'm afraid you have to address things on a case by case basis and figure out WHERE they went wrong.


Even then, you get the hopeless cases(easy fixes often figure it out and do not ask much on line).


EI's CO2 rate might be 15 ppm for a low light tank, or 60 ppm for another.

 

[Marcel G]

I think this graph would represent the nutrient concentration (uptake) with regard to growth rate much better:





This chart is not for any concrete nutrient. It is designed to show the general principles of nutrient concentration and growth. The numbers for nutrient concentration are just as example.

View attachment 13700

View attachment 15079

 

[Tug]

Tom, I'm still reading the abstract.


http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CCgQFjAB&url=http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F226747600_Interactions_between_light_and_CO2_enhance_the_growth_of_Riccia_fluitans%2Flinks%2F0912f50b79f5403c87000000.pdf&ei=n1alVMa6OYLhggS6-4PQDA&usg=AFQjCNGpb8LrlgWWIDvE0fOzewUbavJeIg&sig2=YdXZsAgp4IK_QDzEdrkuKw&bvm=bv.82001339,d.eXY


A good chance you are talking about these tanks at the AGA conference.


http://www.ukaps.org/forum/threads/co2-and-ei.35127/page-3#post-377272


Thank you everyone. Happy new year geeks.

 

[Tom Barr]

I think this graph would represent the nutrient concentration (uptake) with regard to growth rate much better:
View attachment 5259


This chart is not for any concrete nutrient. It is designed to show the general principles of nutrient concentration and growth. The numbers for nutrient concentration are just as example.

Agreed, these are standard uptake vs growth for light, CO2 and nutrients.

 

[Tom Barr]

Tom, I'm still reading the abstract.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CCgQFjAB&url=http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F226747600_Interactions_between_light_and_CO2_enhance_the_growth_of_Riccia_fluitans%2Flinks%2F0912f50b79f5403c87000000.pdf&ei=n1alVMa6OYLhggS6-4PQDA&usg=AFQjCNGpb8LrlgWWIDvE0fOzewUbavJeIg&sig2=YdXZsAgp4IK_QDzEdrkuKw&bvm=bv.82001339,d.eXY


A good chance you are talking about these tanks at the AGA conference.


http://www.ukaps.org/forum/threads/co2-and-ei.35127/page-3#post-377272


Thank you everyone. Happy new year geeks.

Those 9 treatment levels are every basic aquarist range.


But that does NOT include ferts.


The more variables added, the more messy it becomes.


The less you can say about it.


Now at low light/no CO2 gas added, well, we CAN say it will have much less demand, say 10-20X less than the high light/high CO2 treatment.


But there are other factors in real aquariums.


So we really NEED to treat each person and each tank specifically. Trying to move down down between A and B is tough, because you have dependencies.


Then you get folks who are limiting nutrients more than say CO2 or light............and think there's something to nutrient limitations and plants growing "better" with less.


Liebig's law predicts this. Ole and Troels know this, it's the hobbyists that have the issues with it conceptually.


I'm not assuming either, we all 3 talked about it.


Claus and Karen as well.


This is why I help people individually to this day, there's no "one size fits all goals" method or "fix it".


You also can help other things they overlooked that have a cumulative effect of better results/management.


In the paper cited, they used non limiting nutrients in all treatments, thus the nutrients are independent of light and CO2. EI does the same thing.


If they had added say 3 levels of nutrients, say A, B and C..........now the thing gets messy.

 

[Tug]

I would like to represent higher growth rates in plants w/CO2 under the same light/conditions as those grown w/out CO2. Sounds like a great experiment but I would expect, growth rates to increase 2-3x.


I believe this is the advantage plants have. They gather light more efficiently in low light situations - with an established carbon source, like CO2.


What if I try to represent growth x volume of stuff?


The drawing I have here, adds some commonly understood boundaries and plots relative volumes of recommended stuff. It is a drawing, so not pretty. PPS-Pro and EI daily should be moved to the left of stuff but it's a ruff concept - at best.

 

[Tom Barr]

You have 3 parameters, not two, you have 2 dimensions there. you need a 3rd. Or combine light and CO2 over a sliding scale etc.


Growth is a function of all three and several other possible variables, like temp/current, fish load, tap water supplies, water change frequency, trimming, export etc etc.

 

[Marcel G]

There is another problem I see there: the substrate type. You need to account for the substrate also. I mean PPS-Pro and EI without any nutrient-rich substrates can give you much lower biomass yield then PMDD with ADA Aqua Soil Amazonia. So you should have PMDD+gravel, PPS-Pro+gravel, EI+gravel, PMDD+Amazonia, PPS-Pro+Amazonia, EI+Amazonia ... Also I don't understand what do you mean by the 44ppm CO2 on X axis? As Tom said, you should have the same PAR and the same CO2 level during all experiments. So if you need to find out the growth rates at 20 ppm CO2 vs. 40 ppm CO2, then you should do two different series of tests for each ppm level.


This would be great experiment, but how do you want to measure the growth rate?

 

[ak24]

Tug,


In first graph on horizontal axis the co2 reach 44ppm and the growth going down. Pls explain why and what from is this magic 44ppm ? Even if the 44 number is not correct or +- pls explain me this situation. Second graph is not clear.

I think this graph would represent the nutrient concentration (uptake) with regard to growth rate much better:



This chart is not for any concrete nutrient. It is designed to show the general principles of nutrient concentration and growth. The numbers for nutrient concentration are just as example.

No graph available.

 

[Tug]

It was more of a abstract drawing trying to represent some known boundaries. There may be a forgotten reason I use 44ppm but we know over 44ppm it is very difficult to maintain a planted tank with fish. In the first drawing the decline in the curve was meant to mirror the slop of the line from point A to point B due to the reduced PAR poorly represented by the yellow bands. Point C at 120mmol/44ppm CO2, after point C, lower PAR, less growth. I do not mean to suggest that more CO2 then 44ppm will slow plant growth.





kwisats graph, which I wish I had saved, showed more accurately the standard uptake vs growth for light, CO2 and nutrients. I was trying to provide a visual representation of some of the relationships along the way but as Tom points out, the number of dimensions do not accurately represent the number of parameters and as kwisatz stated it did not easily represent soils, although to me it did. It really is hard to represent on a simple drawing like mine but the second drawing avoided that confusion by trying to place growth, light and CO2 along the vertical axis and represent nutrient strategies along the horizontal axis. It's clear to me that it needs work. However, thank you for your input.

 

[Marcel G]

OK, the chart I posted earlier can be seen here.


The "magic" value 44 ppm CO2 is propably also from the note of mine that according to many scientists most aquatic plants reach the photosynthesis saturation point at 1 mM CO2, which is 44 ppm. Actually, some aquatic plants reach the maximal growth rates at 0.5 mM (22 ppm). So it would be better to say that for most aquatic plants 20-40 ppm CO2 should be the optimum level (100% growth rate). At higher concentration the growth rate will decline (but not so dramatically as Tug suggests in his chart). But if you look at the chart of mine, for 90% growth rate you may need only 10-15 ppm CO2. I see no point in supplying more that 10-15 ppm CO2 other then lowering pH under 6.5, in which case some algae species would more readily die (e.g. Audouinella aka BBA, or Cyanobacteria aka BGA).


PS: Look at the Amano tanks in his "Nature Aquarium World - Book 1". You'll find that he used only 9 ppm CO2 (in average) in his 61 tanks. In one of his tank where he grew Rotala wallichii he used only 9 ppm CO2. Think of it.


Marcel

 

[ak24]

Tug


thanks for explanation, especially 1st graph and 44 ppm co2 number.


kwisatz


This chart is clear! But nutrients is general, and one nutrient can do more than others in growth.

...for most aquatic plants 20-40 ppm CO2 should be the optimum level (100% growth rate). At higher concentration the growth rate will decline...

Any research? On this stage I'm not agree with this theory. But this is only my wisdom and experiences, no researches as "base".

 

[Marcel G]

But nutrients is general, and one nutrient can do more than others in growth.

The chart is just a general chart not meant for any specific nutrient (although it can be used for CO2 quite well). Still, the principle applies for all other nutrients, although each nutrient will have a different values (concentrations on the X axis), and a little different curve as well. But you should know that the CO2 concentrations (1mM = 44 ppm) was for a non-limiting environment. So in some limiting environment (like that in our tanks) the actual consumption (nutrient uptake) will be lower. So when aquatic plants under full sunlight (1500-2000 µmol PAR) grow at their maximum speed (100%) under 40 ppm CO2, then under 50-400 µmol PAR (the case in our tanks) they won't probably utilize such a high CO2 level. We limit the aquatic plants in our tanks in many way (not only by light). According to Gerloff & Krombholz, the most demanding aquatic plants (Ceratophyllum demersum, Heteranthera dubia, Elodea occidentalis, Najas flexilis, Vallisneria americana, Zannichelia palustris) need 21 ppm N (= 93 ppm NO3) to reach their maximal growth rate (100%). So by supplying them much lower level of nutrients we limit their growth in many aspects. And thus, they won't be able to uptake other nutrients in optimal way neither. So why would you supply your plants by 40 ppm CO2 (or even more) when you use 5-times lower light level, and 3-5times lower NO3 level then is needed for reaching the saturation point of photosynthesis?


Also, what do you mean by saying "one nutrient can do more than others in growth"? Plants need all the essential nutrients for growth. Some of them they need in much greater amount (like CO2), whereas others are sufficient in quite a low numbers (like NPK), or even in trace amounts (like Fe etc.). But they need all of them to grow well. None of the essential nutrients is more important then others. So how do you mean that?

 

[Tom Barr]

OK, the chart I posted earlier can be seen here.
The "magic" value 44 ppm CO2 is propably also from the note of mine that according to many scientists most aquatic plants reach the photosynthesis saturation point at 1 mM CO2, which is 44 ppm. Actually, some aquatic plants reach the maximal growth rates at 0.5 mM (22 ppm). So it would be better to say that for most aquatic plants 20-40 ppm CO2 should be the optimum level (100% growth rate). At higher concentration the growth rate will decline (but not so dramatically as Tug suggests in his chart). But if you look at the chart of mine, for 90% growth rate you may need only 10-15 ppm CO2. I see no point in supplying more that 10-15 ppm CO2 other then lowering pH under 6.5, in which case some algae species would more readily die (e.g. Audouinella aka BBA, or Cyanobacteria aka BGA).


PS: Look at the Amano tanks in his "Nature Aquarium World - Book 1". You'll find that he used only 9 ppm CO2 (in average) in his 61 tanks. In one of his tank where he grew Rotala wallichii he used only 9 ppm CO2. Think of it.


Marcel

Amano fudges his parameters(or whoever wrote those parameters), there's no way they are all so close.


And the KH/pH chart woukld have to be incorrect in an impossible way to have those ranges of CO2.


I've also measured the pH in several ADA shop tanks, they are much lower than this. 6.2 to 6.0 on average for decent healthy tanks with a KH of 2, PAR about 50 or so along the bottom of the tanks. The pH/KH table will over estimate(you think you have more than is really there), but it will never underestimate the CO2.


Having a pH of 7.0 and KH of 2, there is simply no way to have a CO2 of 15 ppm.


He/who ever is helping him etc to write the book and add the data are fudging things.


CO2 also changes over the day, and perhaps they take the CO2 right after a water change, or after the CO2 supply has been off for a couple of hours, they do not run CO2 for pictures, so at the moment the picture is taken, then it might be 9 ppm........


Cutting the light intensity in 1/2, that makes a huge difference also.

 

[Tom Barr]

So why would you supply your plants by 40 ppm CO2 (or even more) when you use 5-times lower light level, and 3-5times lower NO3 level then is needed for reaching the saturation point of photosynthesis?

Because I'll get algae otherwise. I've done this perhaps hundreds of times.


I focus on the growth and good health, THEN, I go back and measure things.


I do not assume that 40 ppm of CO2 or 20 ppm of CO2, or 9 ppm of CO2 is "good, ample, non limiting".


Once the tank is operating nicely, excellent growth and no algae issues, THEN, I'll measure the CO2.


And it is different for every single tank.


Why shouldn't it be?


Flow is different, surface area is different, plant density is different, light intensity is different, temperature etc.


The methods used for the research: they are typically a single plant in a chamber(or a single plant stem in a pot all placed in a chamber), they are not a densely planted aquaria. The biomass is very low, flow is good. As you increase biomass, within the plant groups, the CO2 drops. We measured 45 ppm near the inflow, then added a lot of Egeria Densa, about 50 stems and roughly dense 18 inch ball. The CO2 inside in the middle was only 15 ppm. I've measure 15-10 ppm in some sections of the plant bunches, but 30-50ppm elsewhere. This was using the Oxygard CO2 probe and their methods.


I can try it with the pH/KH method also, even if it's relative..........it would/should show a good sized difference.


Or the Oxygard method is incorrect.

 

[Marcel G]

Because I'll get algae otherwise.....
I do not assume that 40 ppm of CO2 or 20 ppm of CO2, or 9 ppm of CO2 is "good, ample, non limiting".....


The methods used for the research: ..... The biomass is very low, flow is good. As you increase biomass, within the plant groups, the CO2 drops.


We measured 45 ppm near the inflow, then added a lot of Egeria Densa, about 50 stems and roughly dense 18 inch ball. The CO2 inside in the middle was only 15 ppm.

This argument is really good if we speak about plants, but not as good if we speak about fish and/or shrimps. I agree that when we measure 40 ppm right under the water surface level, in the plant beds we can have hardly 15 ppm CO2. That's one of the reasons why a good flow is so important in planted tanks. On the other hand (if I understand it correctly), you keep 50-70 ppm CO2 in your tank just because you want higher (maybe ~30 ppm) levels at the hard-to-reach places. Although I understand it from the perspective of the plants, I think it's very insensible from the perspective of the fish/shrimps (especially the fingerlings).


Also, in some Amazonia regions there's also around ~10 ppm CO2 in some rivers and streams, and the plant biomass is huge in there, so there should be the same problems with a hindered flow as in our tanks. But obviously plants grow very well in there. Of course the CO2 levels are in some range in all these rivers/streams, but does it mean that the plants need 50-70 ppm to grow well? I doubt it a lot. You are the only one I know who says that he needs 50-70 ppm CO2 to grow his plants (oh, I forgot Clive alias ceg4048 from ukaps.org). And if you have algae under lower CO2 levels, are you really sure it's CO2 issue? How do you know that? If you lower your CO2 levels, your pH will rise also, so you won't have the same conditions any more to know if the algae problem is being caused by low CO2 (in itself) or by higher pH. Also, if you supply your plants with such a high levels of CO2, and then abruptly you drop the CO2 level to 30 ppm, I can imagine that the plant response won't be much positive. But this does not mean that your plants need 50-70 ppm to thrive. Many people I know grow aquatic plants at 10-15 ppm CO2, and their plants are doing very well (Rotala wallichii is no exception in their tanks). Jason Baliban did also used (or still uses) the same low CO2 (and nutrients) levels in his tanks, and said that his plants grew very well under these conditions. You can look at the beautiful tank of my good friend, who uses 10-15 ppm CO2 in this tank: https://dl.dropboxusercontent.com/u/...u_4x24w_jn.jpg (the numbers on the picture are PAR values). By the way, how much CO2 do you think he has in the clump of plants at the rear glass? I doubt it is these 10-15 ppm which he has at the front glass where there are no plants (no hindrances).


So I still don't understand why high CO2 levels (50-70 ppm) should be needed.


Marcel

 

[Dennis Singh]

And if you have algae under lower CO2 levels, are you really sure it's CO2 issue? How do you know that?

I agree with this statement the most. Can you guys elaborate this?


In Tom's defense, I've purchased plants from many people and plants are great, but none other than Tom's, (maybe happy) have I seen plants so thick, so strong that the if you break the stem it snaps like a tree...my 1 cent

 

[Tug]

Amano fudges his parameters(or whoever wrote those parameters), there's no way they are all so close.


And the KH/pH chart woukld have to be incorrect in an impossible way to have those ranges of CO2.

I have read that many asian master chefs will teach you how to slice and dice the food in proper fashion but never give away there true recipe.