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150 ppm co2?

aquanoobie

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And I am sorry I am not familiar with you. Can you show me something you have created that I would be interested in learning more about? I am eager to learn from those that are successful in growing plants. Show me something and it would be a more interesting discussion.
With all due respect, how do we as a community know for sure, you are not taking pictures of your neighbour's tank? You know, as far as internet credibility goes.
 

Hanuman

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This research paper talks about higher CO2 levels inhibiting aquatic plant growth. Who would have thought?

“The critical values of CO2 lay approximately between 0.6 to 1.0 mM (26 to 44 ppm CO2). At this critical CO2 concentration photosynthetic rate reached its maximum and then decreased with increasing CO2.”

1 mM = 44 ppm CO2

Choosing to ignore the researched topic and stirring the discussion to insufficient number of studied plant species and glass box excuses?

The study is about high CO2 inhibiting aquatic plant growth. It has been observed and studied. And the study has demonstrated how higher CO2 levels can be detrimental to aquatic plants. Levels of 30 ppm and higher, recommended by some, can actually be causing more harm than good this study suggests.

I kind of expect, though it takes time, to see posts like, Full CO2, 1/2 CO2 and 1/4 CO2, to gain popularity.
I read the abstract and the results of that study and tried to understand as much as I could considering I am no biologist. Let's get things straight here for a moment. The study does not talk about 'higher CO2 levels inhibiting aquatic plant growth'. It talks very specifically about Elodena densa, not "plants". Full stop. So you claiming that 30 ppm or so of CO2 inhibits plants growth in general terms is a huge extrapolation of facts discussed in that paper. In fact that plant has been known for a long time to be a low CO2 demanding plant which actually does much better with low CO2 levels than with higher levels. This is definitely not the case for most plants we grow in aquariums. This plant has been discussed in the forum. Even for slow growing plants which would do fine with lower CO2 disponilility benefit from additional CO2. I am not making any claims here, just pointing out that making generalities like the one you did is a no no.
With all due respect, how do we as a community know for sure, you are not taking pictures of your neighbour's tank? You know, as far as internet credibility goes.
All is possible. Clearly you have no clue though. Because I don't want to be labeled a Gregg fanboy I simply did a quick google search to show it's at anyone's fingertips. Maybe with today's technology deep fakes are possible though 😚

I guess all those respected people and companies have a conspiracy going on. @GreggZ Where's the pic with you and a guy in front of your tank BTW? Couldn't find it. Did people found out it was photoshoped and you deleted it from the internet?
 
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GreggZ

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With all due respect, how do we as a community know for sure, you are not taking pictures of your neighbour's tank? You know, as far as internet credibility goes.
I guess I should have expected this argument based on who's methodology you favor. It's the same excuse I have heard from that camp for a decade. It's like they have a school that teaches it.

In the end, this is a visual hobby. All the people I know and communicate with share pictures all the time. It's the best tool we have to share results.


Where's the pic with you and a guy in front of your tank BTW? Couldn't find it. Did people found out it was photoshoped and you deleted it from the internet?
Don't be fooled. He's not real. I created a deep fake. Same for all the 1,000's of other pictures I have posted over a very long time. I have a cottage industry going on here creating fake pictures.😄😄
20210130_151530.jpg
 
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dw1305

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Hi all,
I think it's something like vapor pressure / partial pressure x 10^6 = ppm. Probably wrong... but looping in @dw1305 as Darrel probably knows this.
Unfortunately not, I don't have access to Nature as a journal. I think the reason for the fluctuating CO2 levels is to do with the dry and wet seasons in the Amazon basin.
The study is about high CO2 inhibiting aquatic plant growth.
I think the issue for us is that most of the plants we grow aren't really obligate aquatic plants (without a cuticle or stomata etc), but they are semi-aquatic emergent plants and they really want to get at the 420 ppm of atmospheric CO2.

cheers Darrel
 

aquanoobie

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I think the issue for us is that most of the plants we grow aren't really obligate aquatic plants (without a cuticle or stomata etc), but they are semi-aquatic emergent plants and they really want to get at the 420 ppm of atmospheric CO2.
Thank you @dw1305 for clarifying.
You call this plant category semi-aquatic. We have aquatic plants and non-aquatic plants, but what is a semi-aquatic plant? And also how can we tell what is real aquatic and what is not?
Thanks
 

dw1305

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Hi all,
We have aquatic plants and non-aquatic plants, but what is a semi-aquatic plant?
No, we definitely don't have two pigeon holes "Aquatic" & "Non-Aquatic", what we have a continuum from <"xerophytes to hydrophytes"> and there are plenty of plants in the semi-aquatic category.

Because plant producers (Tropica etc) want to grow their <"plants emersed">, they are looking for plants like <"Rotala rotundifolia">, <"Hygrophila corymbosa">, <"Echinodorus"> & <"Cryptocoryne"> spp. etc which will grow submersed, in some cases for very long time periods, before flowering when the water level falls.

Some plants <"are less successful"> long term and will either flower, or die in the attempt.

Here are photos of two Water Crowsfoot Ranunculus spp. (from last week) that are on the aquatic end of "semi-aquatic". <"Ranuculus hederaceus"> and <"R. baudotii">.

R_hederaceus.jpeg

R_baudotii.jpeg


cheers Darrel
 

MichaelJ

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Unfortunately not, I don't have access to Nature as a journal.
Hi Darrel and @Yugang:
In water it turns out there is a fairly linear correlation between partial CO2 (uatm) and ppm. The conversion depends on temperature and salinity. At 20C at extremely low salinity it's approximately a factor of 0.0017. So for converting the scale from pCO2(uatm) to CO2 ppm in Outgassing from Amazonian Rivers and Wetlands as a Large Tropical Source of Atmospheric CO2. E. Richey et. al. figure 3a and 3b:

pCO2(uatm) -> CO2 ppm.
2 x 10^3 = 3.4 ppm.
4 x 10^3 = 6.8 ppm.
8 x 10^3 = 13.6 ppm.
12 x 10^3 = 20 ppm.


Cheers,
Michael
 
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aquanoobie

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I think the issue for us is that most of the plants we grow aren't really obligate aquatic plants (without a cuticle or stomata etc), but they are semi-aquatic emergent plants and they really want to get at the 420 ppm of atmospheric CO2.
Hi @dw1305
I guess I used wrong word. Instead of,

"The study is about high CO2 inhibiting aquatic plant growth."

I should have said,

"The study is about high CO2 inhibiting growth of a plant we keep in aquariums."

Egeria densa - Tropica Aquarium Plants

Then it would't create such havoc. My apology.
 

dw1305

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Hi all,
The study is about high CO2 inhibiting growth of a plant we keep in aquariums
I've been thinking about this and I'm guessing that obligate aquatic plants from hard water (so plants which always <"get their DIC / TIC in the form of HCO3-">) are likely to be inhibited (or not be able to utilise) higher levels of CO2, because they are never going to experience them in the wild, they are adapted to using bicarbonate (HCO3-).

wqassess3bpict1-gif.gif

<"This doesn't apply to floating plants">, because they always have access to atmospheric gases, via the stomata in their upper leaf surfaces. This access to atmospheric gases (<"Diana Walstad's "aerial advantage">) is why <"floating plants can utilise more of the nutrients in the water">.

cheers Darrel
 
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KirstyF

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It seems entirely logical that there would be some ‘aquatic’ plants that prefer lower Co2.

In our aquariums, folks are often looking for ‘optimal’ growth and form, whatever that looks like in our eyes. (The plants are probably less bothered about being perfect) Optimal growth conditions are always going to be different for different plants and therefore practical application of our husbandry methods can only be based on finding an appropriate ‘centre line’ for whatever selection we choose to keep.

My question would be, why wouldn’t there be plants that are inhibited by high Co2? Simply on the basis of ‘all things under the sun’ there are bound to be some that fit that bill and the family of obligate aquatic plants, that are never (in nature) exposed to atmosphere and have evolved therefore to live permanently in a lower Co2 environment, may logically contain those candidates.

I’d guess however that there are also obligate aquatics that would do perfectly fine with higher Co2. Figuring out which are which may be entirely dependant on popularity of, or level of desire to keep, a specific plant.

After all, much of the knowledge of how to best keep aquarium plants will come from aquarists so some of these plants may be ‘known’, others not so much.

So, again, with no scientific evidence, you can probably take out any and every aquatic plant that can be successfully grown emersed (makes sense right) so then you just gotta figure out if any of your obligate aquatics perform better with lower Co2 and then, to achieve optimal form, not grow them with plants that prefer ‘high’ Co2. (Oh and then match them to their other optimal parameters, such as nutrient/light levels etc….Easy 👍………ok maybe not!! 😏)

If of course the ‘high’ Co2’ level that inhibits such plants is, in fact, notably higher than 30ppm ish, alot of us can just go back to watching eastenders now. 😊

And anyone that wants to run Co2 at higher than 44ppm and also grow Elodea Densa at optimum, might be out of luck I guess.

As for full, 1/2 and 1/4 Co2. If full is 30ppm (and most folks would consider that to be the case) then there would need to be strong evidence that a number of plants are detrimentally effected at levels lower than 30ppm for that to ever be relevant and I’m not seeing that in this study!

Anything above 30ppm might need a new category. Full plus? super full maybe? 😊 but, as this study allows up to 44ppm (I believe!) I’m still thinking the list of plants that would actively suffer within any range that is normally implemented by aquarists would be pretty small.

Just my 2pennies worth! 😊

As for 150ppm. I’d be interested to see physically how that could be achieved 😳but in a practical sense, seems like ‘Co2 is free’ taken to a whole ‘nother level! 😂
 

aquanoobie

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Hi all,

I've been thinking about this and I'm guessing that obligate aquatic plants from hard water (so plants which always <"get their DIC / TIC in the form of HCO3-">) are likely to be inhibited (or not be able to utilise) higher levels of CO2, because they are never going to experience them in the wild, they are adapted to using bicarbonate (HCO3-).

wqassess3bpict1-gif.gif
Interesting.
If we take this idea further then submerged plants utilizing bicarbonate have as much carbon available in aquariums with medium to high KH as in the nature under direct sunlight. We can't give them more KH unless we go for unusually hard cave water levels. So this is the maximum carbon they get under full sun.

But with CO2 as a carbon source we don't have this option of maxing out CO2 due to fauna limits and the many unknown in CO2 infusion process. Or I am completely wrong?
 

erwin123

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I hope MrTank has not been scared away from his own thread! I'm looking forward to photos of the plants in his 150ppm CO2 tank and what the differences are compared to a 'regular' 30ppm CO2 injection.
 

dw1305

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Hi all,
If we take this idea further then submerged plants utilizing bicarbonate have as much carbon available in aquariums with medium to high KH as in the nature under direct sunlight. We can't give them more KH unless we go for unusually hard cave water levels. So this is the maximum carbon they get under full sun.
We used to <"run an experiment"> to look at oxygen evolution <"using Cabomba caroliniana">, with dilute sodium bicarbonate (NaHCO3) as the <"inorganic carbon source">.

cheers Darrel
 

dw1305

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Hi all,
What do you think about them positioning the plants upside down during the test?
I'm not sure it really matters. You only get visible pearling once the plants internal spaces (<"lacunae and aerenchyma">) are saturated with oxygen and aquatic plants are very efficient at <"moving oxygen internally">. She talks about this from about 10:30 in the SAPS video. If you search for <"Radial Oxygen Loss"> it will give you some references.



Originally the experiment was done using the inverted funnel method, so I guess that was the original reason for using the plant inverted.

cheers Darrel
 

sparkyweasel

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This research paper talks about higher CO2 levels inhibiting aquatic plant growth. Who would have thought?
The plant fragments were observed at different pH and CO2 levels, for only 30 minutes at each combination.
I do not think we can assume that we would see similar results in an aquarium situation.
We know that;
Plants can adapt to various conditions, within limits.
Plants take time (often more than 30mins) to adapt to new conditions.
Plant fragments do not always behave identically to whole plants.
 
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