Liquid CO2

noodlesuk

Member
Joined
21 Jul 2020
Messages
182
Location
Oxfordshire
Is it beneficial? I started using it (Easy-Carbo) when I set up my first "proper" planted tank, mainly because from the manufacturing blurb, it seemed to make sense. However I have since read posts on other forums about it not being beneficial, waste of time and can damage some plants. These claims seem fairly anecdotal, based on personal preference. Everyone seems to agree it can help control algae.

I just wondered what the consensus was? I have a 20L low tech, with quite a high plant mass. It's not a pain or a big cost for me to add liquid CO2 daily, but wonder if I'm wasting my time? Guess I could just stop it and see what happens!
 

ScareCrow

Member
Joined
28 Jan 2019
Messages
88
Location
South west
I can only supply anecdotal evidence based on what I've observed in my tank. For the most part I stick to easy plants. The only non easy plant is P.helferi. With the addition of 'liquid carbon' I can grow P.helferi without it I can't. Those with soft water would probably get away without but unfortunately for my plants my water is very hard. I intend to switch to rainwater/tap mix and actual CO² if for no other reason than 'liquid carbon' isn't a particularly nice chemical, although safe if handled correctly.
 
Joined
27 Oct 2009
Messages
2,860
Location
Cumbria
It's not a pain or a big cost for me to add liquid CO2 daily
It has nothing to do with "co2" really. I think the biggest bone of contention is the amount of carbon it adds as oppose co2, it really is a tiny amount relatively speaking. There is a lot of science going on about why you should or shouldn't use it. People tend to think the algaecide properties are more beneficial than the actual carbon part.
I've read extremely well informed plant people explaining why they wouldn't use it but on the other hand I've also seen some nice planted tanks by equally well informed people who do. The million dollar question is would they still have had those nice setups if they hadn't. It's an age old argument that still rolls on.
 

Zeus.

Member
Joined
1 Oct 2016
Messages
3,559
Location
Yorkshire,UK
This pm had had with Clive some time back may be insightful
The main problem discussing and experimenting with LCO2 is that of our collective ignorance. We really do not understand the How and the Why of it's mechanism. We have a fairly well grounded, basic understanding of the photosynthetic processes.
A. We understand that Rubisco's job is to capture CO2 molecules and to deliver the molecules to the Calvin Cycle reaction centers. We know that Rubisco is hugely expensive and consumes a lot of resources to produce and to maintain. In low tech tanks, where the CO2 concentration is low there is a much higher density of Rubisco in the leaf because you need more of the protein to capture the small amounts of CO2. In gas injected tanks, the Rubisco density in the leaf is lower.

B. We also know that during Calvin Cycle, the fixing of Carbon involves some intermediate carbohydrate products until the final product is a type of glucose.

So, for item A. we know that when the plant senses that high concentrations of CO2 is available, it responds by reducing the production of expensive Rubisco. When it senses a lower CO2 concentration it must increase Rubisco production, however because this protein is so complicated and heavy, the increased production requires 2-3 weeks in order to change the density in the leaf to match the new gas concentration level. So it is much easier to reduce production than it is to increase production. When increasing gas injection therefore, it hardly takes any time to see an improvement in health. When lowering the concentration, the plant will suffer because it must now ramp up Rubisco production to account for the loss of CO2 availability.

When increasing the light, the plant must reallocate resources from Rubisco production/maintenance in order to deal with the increased radiation. This may entail new pigment production for protection. When the light is reduced, the plant then reallocates the light gathering proteins and can devote them to Rubisco production/maintenance.

So when we mess around with light and gas, we have some degree of predictability.

But no one except for Tom Barr and Seachem know what LCO2 is and why it works. We do not know if it is actually converted to CO2 and affects Rubisco production, as in item A., or whether it is converted to one of the carbohydrate intermediaries in Item B. and therefore shot circuits Rubisco management.

The advice to carefully adjust LCO2 upwards has mostly to do with not knowing what the toxicity level for various plants and animals are and has very little to do with the mechanism of Rubisco or the adjustment of the leaf to CO2 levels.

You cannot really compare a plant's performance from one tank to another because we have very little measurement data from which to draw any kind of conclusion. Maybe PAR is lower in the smaller tank. Maybe flow over the leaf is better. Maybe gas is dissolved better at that specific location. We have no idea. So best not to draw any conclusion. The sample in the big tank can maybe be moved around to see if performance increases. That's about the best you can do, really. P. helferi is kind of slow to gain momentum but should perk up eventually. On the other hand it might actually be telling you something about the big tank...

About the only other thing you could do to eliminate LCO2 toxicity is to reduce it, observe the helferi and then increase it, or add it to the small tank to see if there are deleterious effects.

It's all stabbing in the dark mate, sorry...

Cheers,
Clive

Think once your tank has filled in slowly cut down the dose and then stop dosing and watch your plants
 

Siege

Member
Joined
11 Aug 2017
Messages
1,219
Location
Cambridgeshire, UK
I agree with all the above.

I use full co2 and have very hard water.

Have done a few experiments on my trident ferns In particular. With the addition of liquid carbon they are much greener with fewer brown spots. It was a marked difference. I use it daily as per instructions.

It went even better with the addition of weekly ADA Green Gain (which is mainly a phytohormone) alongside liquid carbon. I’m not suggesting you add this as you are not using full co2, just a note really.

@Geoffrey Rea might be able to add more. I know he has gone further with experimentation and adds liquid carbon carbon by the bucket load! 😂
 
Last edited:
Joined
27 Oct 2009
Messages
2,860
Location
Cumbria
But no one except for Tom Barr and Seachem know what LCO2 is and why it works.
I think Tom quite openly discusses it these days. Once when I was chatting with him he mentioned the amount of carbon that was made available as the product breaks down in the tank. If I find it again I'll post it. The crux of it was that at normal dosing the amount of carbon released over the active period could similarly be achieved just by having good gas exchange bringing the natural co2 into equilibrium. As a carbon source it wasn't very effective. The benefits of causing an uncomfortable place for algae to live while giving the plants the upper hand with nutrients far out weighed any carbon related benefits. Was my understanding anyway...
 

noodlesuk

Member
Thread starter
Joined
21 Jul 2020
Messages
182
Location
Oxfordshire
Thanks everyone for the responses, lots of great information, including different view points. Will go away and do a bit more research and, once the tank is established, maybe start experimenting with reducing the LCO2 in my tank and see what effect it has.
 

Nico Felici

Member
Joined
16 Oct 2020
Messages
34
Location
London
Noodles, just like you I have a low tech nano scape and been wondering about the use of liquid Co2. My impression from the research I made was very similar to what has been discussed here - general confusion as to whether it really helps with plant growth and to what extent. I did read on multiple occasions though of people reporting greater effects on small tanks (50litres and under).
Decided not to try it for now or not unless my plant start struggling without Co2. I'll be following your posts though and see what your thoughts are in case you decide to give it a go.
 

Witcher

Member
Joined
15 Jan 2020
Messages
302
Location
London
Is it beneficial? I started using it (Easy-Carbo)
It has nothing to do with "co2" really.
Assuming we are talking about Glutaraldehyde (Easy Carbo is a Seachem's brand name for approx 2.5% aqueous solution of Glut) it works without any doubt and Carbon dioxide is an effect of metabolism caused by bacteria (it don't happen in sterile conditions).

No appreciable degradation of [14C]-glutaraldehyde was observed in sterile aqueous buffer solutions at pH 5 and 7 over a 31-day period (Table 3).
(...)
The pH of the incubated river water was 7.7 at collection and ranged 6.3–7.6 during the experiment in the aerobic metabolism study (Table 4). Dissolved oxygen concentration was 4.9– 7.4 ppm. The microbial activity in the water was 1.0 3 105 CFU at the start of the experiment and showed a marked decrease at 4 h (2.5 3 103 CFU). The microbial activity rebounded to pretreatment level after 1 day. In the initial stages of the experiment (0–4 h) . 90% of the applied radiocarbon was found in the water phase. No significant radioactivity was found in the methylene chloride plugs or in the ethylene glycol trap throughout the study. During the period of 1 to 30 days, the proportion of aqueous radiocarbon decreased from 67% to 14% with a concomitant rise in the evolution of 14CO2 to 68% after 30 days, whereas the proportion of radiocarbon found in the sediment decreased slightly from 20% to 12%. Overall material balance based on the recovery of radiocarbon was 93.3 6 9.8%. [ 14C]-glutaraldehyde was the predominant component of the radiocarbon (88.9%) in the aqueous phase at the start of the experiment, but it decreased rapidly to 0.2% after 2 days (Table 5). Based on the time course of the observed glutaraldehyde concentrations, the pseudo-first-order half-life of glutaraldehyde catabolism in this river water–sediment system under aerobic conditions was 10.6 h. The major metabolite of glutaraldehyde produced by microbes in an aerobic aquatic system was carbon dioxide, with glutaric acid formed as an intermediate. Comparison of the HPLC retention times and the TLC profiles of authentic reference standards confirmed glutaric acid as a metabolite. HPLC analyses revealed that CO2 was the predominant species detected in the aqueous phase after 48 h. The presence of 14CO2 in the aqueous phase was confirmed by the quantitative yield of radiocarbon from the precipitate of an aqueous sample treated with barium chloride. The identity of CO2 as a metabolite was confirmed by comparison of the HPLC retention time of authentic 14CO2 released from the acid hydrolysis of [14C]-NaHCO3.

Source (easy to find on the web): Aerobic and Anaerobic Metabolism of Glutaraldehyde in a River Water–Sediment System. H.-W. Leung.

And this is the effect of long term daily use of glut in my tank (no gaseous CO2 system but very strong light) - image is a little bit sh.tty but please note big bunch of Ludwigia inclinata above Didiplis Diandra - it usually melted in my tank before use of glutaral and I've never seen it thriving in any tank without supplied CO2.

20200606_132225.jpg


Glut + 0 ppm NO3 and Mg for approx. 10-14 days:
20200616_103813_.jpg


And juvenile Ludwigia pilosa below P. stellatus - another plant where CO2 is a must for it to grow (it reached water surface within 20 days or so):

20200613_224457.jpg
 

X3NiTH

Member
Joined
13 Apr 2014
Messages
1,034
With or without extra gaseous CO2 I believe a Bioavailable carbon source addition is beneficial it doesn’t necessarily have to be a Biocide like Glut although the algaecidic properties are a bonus. I have never been able to use Glutaraldehyde as my other half had to use it (neat) on a daily basis for sterilising reusable medical intervention equipment in the past (thankfully it’s no longer used) and she would rather not be exposed to it again.

The radiocarbon study snippet demonstrates that bioavailable carbon ends up as CO2 only once it has been metabolised by an organism which has uptaken the carbon chain molecule, that carbon can either be used to build tissue or expunged as CO2 through respiration. Where that Carbon comes from either from a sugar, Humic or Fulvic Acid, Tannic Acid, Citric Acid, Acetic Acid or Vodka wouldn’t matter it’s all bioavailable carbon, organisms be it bacteria or plants won’t differentiate because they just see it as carbon and if it come with a biocide attached then either the organism will perish or it will adapt to the source. I use Microbe-Lift BioCO2 because it’s Humic Acid which has a decent amount of carbon and it’s highly plant available.

Any carbon is better than no carbon, I’m sure somebody out there would dose nano diamonds if it was beneficial for plant growth, although judging by the price of some supplements it can certainly feel like you already are!

:)
 
Joined
27 Oct 2009
Messages
2,860
Location
Cumbria
@Zeus. I couldn't find the discussion with Tom, if I remember right it was on Facebook somewhere. I did come across this which was pretty much along the lines of the conversation.
Using glutaraldehyde or commercial “liquid carbon” products as a “carbon source” also just plain doesn’t work. While glutaraldehyde does contain a minimal amount of carbon, using a standard dose, it releases 2.2 ppm of carbon over the first ten hours. So if the rate of dissolution were linear (which it isn't) this would only release 0.2 ppm per hour. Atmospheric equilibrium from gaseous exchange provides 3-5 ppm of CO2 at pretty much all times. So that means that doing absolutely nothing provides 15-25× more CO2 than "liquid carbon". All just by providing good circulation in your tank.
Taken from https://www.sunkengardens.net/blog/...d-co2-and-the-dangers-of-glutaraldehyde-az2w7 AS is evident in the thread we know far too much about the product these days for Tom to be concerned about any possible NDA's. I'm pretty sure Seachem Excel which Tom was involved in was a slightly different chemical make up than reg Glute though. To be fair I hit the point where I wasn't sure what I was putting in the tank so just use co2 or don't and pick plants wisely. At least I sort of know what's going on with them :D
 

Similar threads

Top