Long term effects of co2 exposure

[Soilwork]

We also know that many people breathe an air like this (think of it as of additional amount of CO2 injected into balanced water environment):
View attachment 203340
while others breathe an air like this (think of it as a water with naturally balanced amount of CO2) :
View attachment 203341

Do people living in conditions like on the 1st image die immediately? Certainly not.
Are they more healthy than people living in the conditions like on the 2nd image? Well... some may argue that there's no difference. It's mostly those who are causing dirty air or scientists paid by them to prove that everything is ok.

And yes, water constantly saturated with 30ppm of CO2 is way above average, let's round average to 10ppm so we have 200% more.

Yes, well I’m just stating a fact. The fish don’t die at 30ppm co2. The long term effects are unclear I’ll agree but I don’t want to make assumptions about averages either because it’s becoming apparent that the data may be unreliable.

I’m not a co2 user but I don’t want this to become a discussion based on what we believe. Only what we have seen in our experiences or with verified proven information.

 

[PARAGUAY]

We know fish in their habitats have a ordeal day to day ,small tetras lucky to exceed 12 months with predation ,maybe that's why they breed so young? Also parasitic infection. Even the predators get predated,and many millions die through drying up creeks in the dry season, .. In the CO2 aquarium done right with well planted healthy plants fish exceed many lifespan assumptions.
George Farmer has some lovely Lemon Tetras which think he's had a time, (hope it's alright to mention George )and Green Aqua showroom and the ADA gallery not all those set ups are taken down after a period but the fish look very good and happy.
CO2 has to handled with care of course ,as does feeding and general maintenance. of course but that applys to any aquarium set up

 

[MichaelJ]

I’m not a CO2 user and probably never will be. It’s mostly because I don’t need - or see a need for the added complexity - I’m fine with the slightly limited plant selection (carpet plants such as Monte Carlo comes to mind) and with the slower growth I’m getting at equilibrium levels - often quoted as peaking out at ~3 ppm, but could be as low as <1 ppm. depending on water temperature, surface agitation , plant mass, photo period etc. I can definitely appreciate the benefits of CO2 injection in an otherwise well-run tank (I do think it is cheating of course ) , but I often wonder if anyone ever did a survey of what you would get in terms of plant growth/health at various saturation levels say 7 ppm, 15 ppm, 20 ppm vs the frequently quoted target of 30 ppm which seems somewhat arbitrary and high to me… why not 10 or 25 ppm?… considering what can be accomplished without any CO2 injection at all in a well kept low tech tank, I figure there must be room there to explore? Is there any such thing as lean CO2 injection ?

Cheers,
Michael

 

[_Maq_]

I've read some papers on CO2 influence on plant growth. These conclude that so called half-saturation constant for most plants lies between 100 to 200 µM (4.4 to 8.8 mg/L). From that we can derive the following graph:

Fifty per cent growth (in relation to maximum) can be achieved in the range from 4.4 to 8.8 mg/L CO2. At 20 mg/L we can get something between 69 and 82 %. At 30 mg/L between 78 and 88 %.
In fact, in my country there's a remarkable number of hobbyists who inject about 10 mg/L. Tom Barr's methods are not held in high esteem.
-=-=-
There are studies which evaluated effect of CO2 concentration on commercially bred fish. They showed that above cca. 10 mg/L mortality is higher and growth slower.
-=-=-
Prof. Pavel Pitter has written a textbook called "Hydrochemistry". He worked on it for 50 years, and it was published in five updated and upgraded editions. This textbook is in wide use in universities in Czech Republic and near abroad.
On the concentration of CO2 in natural waters he stated that levels from decimals to units of milligrams per liter are normal, while values above 10 mg/L are an exception.
We should keep in mind that the level of CO2 is normally in linear connection with O2 "burned" by microbes and other organisms through respiration. Therefore, if there is much CO2 in given locality, we can assume that there is too low level of oxygen there for fish and higher plants to survive.

 

[dw1305]

Hi all,

but I often wonder if anyone ever did a survey of what you would get in terms of plant growth/health at various saturation levels say 7 ppm, 15 ppm, 20 ppm vs the frequently quoted target of 30 ppm which seems somewhat arbitrary and high to me… why not 10 or 25 ppm?…

Former member @Marcel G <"tried 15ppm CO2">, I'll see if I <"can find the thread"> elsewhere. Here <"Akvaristika">, in English: <"Aquarium">

I’m not a CO2 user and probably never will be. It’s mostly because I don’t need - or see a need for the added complexity - I’m fine with the slightly limited plant selection (carpet plants such as Monte Carlo comes to mind)

Same for me, I'm never going to be a CO2 user. I would say that the main advantage of adding CO2 is that it allows you to grow plants that aren't really suited to <"full-time life submerged">. These plants are <"fine" for the aquatic plant producers">, bit I'd argue "not fine" for the majority of hobbiests.

cheers Darrel

 

[Andy Pierce]

In fact, in my country there's a remarkable number of hobbyists who inject about 10 mg/L. Tom Barr's methods are not held in high esteem.

This is fine, but you'll need to change your drop checker solution from 4 dKH to 1 dKH for the checker to be maximally informative around the 10 ppm level (Drop checker - Fireplace aquarium). I must say lately for my CO2 injected tank I haven't particularly tried to push up the CO2 levels - I think I've been around 15 or 20 ppm for a while now.

 

[LondonDragon]

I must say that after my stems died off due to the Barbs not liking too much CO2, and I just keep less demanding plants (also means less maintenance), I have tuned it down a lot also, my 5Kg bottle on a 200l tank lasted over 18 months. I am considering getting rid of it, or just keep it very low as it is at the moment, also I have reduced my lights to about 80% also for 4 hours and only on 6 hours a day, rumps up to 80% over an hour and back down to 0% over an hour! I have been reducing the ferts also! might turn the large tank into the same as my other 4, no CO2 and no ferts!

 

[Soilwork]

Hi all,

Former member @Marcel G <"tried 15ppm CO2">, I'll see if I <"can find the thread"> elsewhere. Here <"Akvaristika">, in English: <"Aquarium">

Same for me, I'm never going to be a CO2 user. I would say that the main advantage of adding CO2 is that it allows you to grow plants that aren't really suited to <"full-time life submerged">. These plants are <"fine" for the aquatic plant producers">, bit I'd argue "not fine" for the majority of hobbiests.

cheers Darrel

I had access to Marcels work. He also concluded that growth rates with co2 injection were not linear. For example if you halved the amount of co2 growth rate dropped to about 90% of what had been previously measured. I’m not sure however if it was considered that plants may still have been running on stores.

I no longer have access.

 

[Soilwork]

I had access to Marcels work. He also concluded that growth rates with co2 injection were not linear. For example if you halved the amount of co2 growth rate dropped to about 90% of what had been previously measured. I’m not sure however if it was considered that plants may still have been running on stores.

I no longer have access.

Actually this is incorrect. This was in relation to nutrients. Though technically co2 is a nutrient.

By the way you no longer need a password to enter his website.

Aquarium

golias.net

 

[John q]

Fifty per cent growth (in relation to maximum) can be achieved in the range from 4.4 to 8.8 mg/L CO2. At 20 mg/L we can get something between 69 and 82 %. At 30 mg/L between 78 and 88 %.

Interesting stuff maq, I'm assuming this equation is similar to the standard growth versus light/nutrient uptake chart? Either way its Interesting.

 

[hypnogogia]

I rememenr when I first started injecting CO2, I had a system from Tunze. Their advice on setting it was to set the pH meter at 0.5 above the measured value at lights on. Irrespective of the accuracy of the meter, their argument was you should really only replace the CO2 that plants take up when lights are on, after maximum CO2 concentration after a night of respiration from both plants and fish.

 

[Hanuman]

Christel has answered to me but I am still awaiting one email from her with further details. I will post everything once I receive it.

 

[_Maq_]

I'm assuming this equation is similar to the standard growth versus light/nutrient uptake chart?

Michaelis-Menten equation describes successfully many biochemical processes where velocity is a function of substrate [concentration]. But at the same time, there are many exceptions to this rule.
Sometimes the dependence is linear, esp. with close to zero substrate. On the other end of the curve, reverse factors (like toxicity, phototoxicity a.o.) often modify the curve. In the case of CO2, some sources say that from cca 0.6-1.2 mM (26-53 mg/L) toxic effect on plants increases markedly and supposed maximum growth is de facto unattainable even if light is not the limiting factor.

There's a group of hobbyists who inject far more than 30 mg/L CO2. I do not comment it from my experience because it's obviously very far from that. Yet based on scientific research, it ought to be quite a waste of substrate (CO2), indeed, possibly harmful to plants (not to mention animals and microbes).
One possible explanation is this: With increased concentration of CO2, plants reduce production of chlorophyll, BUT they do not reduce production of anthocyanins. This makes plants redder. This effect is possibly still at work when CO2 concentration exceeds 30-40 mg/L. So, it does not make plants grow better/faster, but still makes them 'better' coloured. Possibly.

Another point to mention is water flow. Appropriate water movement can make diffusive boundary layer on plants' leaves thinner, and thus have the same effect as increased concentration of CO2; at the same time, it can decrease substantially the intensity of photorespiration (a largely wasteful process caused by high oxygen concentration around chloroplasts).

 

[Soilwork]

I’m not a CO2 user and probably never will be. It’s mostly because I don’t need - or see a need for the added complexity - I’m fine with the slightly limited plant selection (carpet plants such as Monte Carlo comes to mind) and with the slower growth I’m getting at equilibrium levels - often quoted as peaking out at ~3 ppm, but could be as low as <1 ppm. depending on water temperature, surface agitation , plant mass, photo period etc. I can definitely appreciate the benefits of CO2 injection in an otherwise well-run tank (I do think it is cheating of course ) , but I often wonder if anyone ever did a survey of what you would get in terms of plant growth/health at various saturation levels say 7 ppm, 15 ppm, 20 ppm vs the frequently quoted target of 30 ppm which seems somewhat arbitrary and high to me… why not 10 or 25 ppm?… considering what can be accomplished without any CO2 injection at all in a well kept low tech tank, I figure there must be room there to explore? Is there any such thing as lean CO2 injection ?

Cheers,
Michael

Didn’t Amano run his tanks around 10ppm co2?

 

[John q]

Didn’t Amano run his tanks around 10ppm co2?

Allegedly 15 ppm. Factually?

 

[dw1305]

Hi all,

Didn’t Amano run his tanks around 10ppm co2

Allegedly 15 ppm. Factually?

I think he did, we have a thread somewhere, but <"not this one">. You can't search for "CO2" and "Amano" isn't a very useful search term, so it may take a while to find,

cheers Darrel

 

[Hanuman]

Below are my emails to and answers from Christel. I quote:

page 606 values of 125, 100, 95 and 84.4

and please answer tigertim: page 606 - that's O2 = Oxygen not CO2

Does it say how the CO2 is calculated? Surely they haven't just used the measured KH and pH and then used the tables to determine the CO2 level - as scientists they'd surely know to look at the pH difference from a degassed sample as we do in a tank for pH profiling?

I think you expend too much attention and effort to those incomplete data. Par example, 49.5 mg/l CO2 is quite possible if there's an underground source of water nearby. Do we know whether this is the case? Do we know the level of organic pollution of that locality? Do we know that any fish or plants were able to live at that particular locality?

My first email to Christel:
Hello Christel,

I am writing this email to ask you for your input. Could you please comment in UKAPS forum on the CO2 figures we can see on those table around page 600 onward of your latest book? Some numbers seem rather high and we are struggling to understand how CO2 can be so high in natural habitats. There is a footnote that says that CO2 was calculated opposed to measured, so this begs the question how was CO2 calculated. These numbers don’t even seem to match the infamous dKH/PH table.

There is actually an ongoing threat in UKAPS forum where we are discussing this but we are all at odds on how these numbers are possible. Here is the threat: Long term effects of co2 exposure

We would really appreciate it if you could comment on this. You could also answer by email if you prefer and I will convey your answer in the forum.

In any case, thank you for taking the time to read me.

With my best regards,

Her answer:

I hope nobody doubts my data. All measurements that were possible on site, I made at the natural habitat electronically as well as with reagents. All other tests were done from my samples in the Tetra lab, as well as the calculations of CO2 values by chemists. Yes, indeed CO2 values can be sometimes very high in natural waters, for example in spring areas (Thailand), very fast flowing water, and black water biotopes. But of course these CO2-levels are mostly much too high for the culture of fish. I am not the first to publish water analyses. The pioneer was Kaspar Horst, managing director of the Dupla company at that time. I sent 2 copies to Paul via mail from his book (1986): Pflanzen im Aquarium (in German). Look once at biotope 9 in the 1st copy (Sri Lanka) and line 5 (Thailand) in the 2nd copy. Regards, Christel

To which I answered:
Dear Christel,
Thank you very much for your answer. Highly appreciate it. I also hope you are well and recovering.

Just to be clear, no one is putting into question your data. We are just surprised of such high CO2 levels and how they were calculated since there is a foot note specifically that states that CO2 was calculated. By the way, what would cause such high CO2 levels? CO2 loaded underground water sipping from river beds?

Could you please give more details on how that CO2 was calculated by chemists? This is pure curiosity.

Again thank you for your time and answers.

With my best regards,

Her answer:

Good evening Paul,

Sorry for the late reply. I have not forgotten you, but had too much to do. Tropica had sent me Bucephalandra for determination, which is not easy.

Tetra lab works with a formula to calculate CO2 content from carbonate hardness and pH. This formula is a company secret, even I do not know it. I need to measure the pH as accurately as possible in the natural location because it changes in the water sample. The carbonate hardness is determined much more accurately in the laboratory than we can do with our reagents. Determining the CO2 content at the natural site makes little sense, because our reagents are much too inaccurate.

I am sending a table from another book of mine (Planted Aquariums), these data are also calculated, see the attachment.

High CO2 content: Yes, of course in spring areas, where the water comes from the underground to the water surface.

I hope I answered all questions.

Best regards,
Christel

And here are the attachments she sent:

 

[hypnogogia]

Thanks for checking @Hanuman. Personally, I'm disappointed to read that an author is publishing data without being able to verify its accuracy.

 

[Witcher]

Just to be clear, no one is putting into question your data.

Why not? Questioning the results its the essence of science and research, while not questioning anything is an essence of faith and dogma.

Tetra lab works with a formula to calculate CO2 content from carbonate hardness and pH. This formula is a company secret, even I do not know it.

CO2 (mg/L) = 10^(pH - pKa) x KH x 3.467 - of course we assume that the only source of alkalinity in the water is from carbonate and bicarbonate ions as per Tetra's "secret" formula.

3.467 factor is used for conversion from from mg/L to ppm.

I think the fact is that researchers (including Kaspar Horts mentioned by Christel) do make mistakes or their methods of measurements may be wrong, what is also wrong that they will never admit it as their credibility is on the stake.

 

[Ria95]

Kasselmann‘s reply points towards a standard practice of determination of total inorganic carbon in the lab with various titration points ... This is indeed much more accurate compared to the alkalinity based test determination of KH at the hobby level. CO2 probes are not only expensive but also a pain to calibrate for accurate readings, per manufacturer instructions often requiring re-calibration during the same measuring.

The point that all measurements are point measurements and there is a wide degree of variation stands. Lack of funding and not lack of interest is likely the reason. For example Esthwaite Water has a reported average of 5.2 ppm CO2, but near the substrate this more than doubles to 12 ppm CO2 allowing more plant growth. Plants and fish will try and live wherever they can, optimal conditions are rare in the process of living.

The half-saturation constant is not related to growth but to the nutrient uptake rate. It‘s given per time and per weight of plant. Thus from uptake of one nutrient to growth rate there are some Olympic jumps to be made. A relative low half- saturation means an efficient uptake under the environmental conditions. There is little reason why we should limit our dosing targets based on it.

A while back, a friend gave me a frequently referenced paper on the topic from Maberly and Madsen 1998: ‘Affinity for Co2 in relation to the ability of freshwater macrophytes to use HCO3 ‘. This show a nice graph of Myriophyllum verticillatum and M. spicatum . M. verticillatum has a half-saturation constant of 5.5 ppm CO2 but uptake rate only plateaus somewhere after 18 ppm CO2. M. spicatum doesn‘t show the any signs of slowing down / plateauing over the test range (up to 35 ppm CO2), telling me that the concentration of maximum uptake rate has not been achieved. For M. spicatum, the authors put the half-saturation constant for CO2 at 24 ppm CO2.
So in the same genus we have two species with a half saturation aprox. 5 times higher. A reference with values for at least 50% + of the plants in Kasselmann would be nice, failing that, I don‘t see how we can say anything about most plants.