# CO2 at 400 ppm



## Victor (30 Jul 2014)

Hi, guys! There are any problems to keep CO2 at aprox. 400 ppm in a tank without animals? Could I kill the benefic bacterias due a very low ph? I think the ph will drop than 5,0, something about 4,8. Thank you in advance.


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## Vazkez (30 Jul 2014)

Hi there,

just wondering why need 400 ppm? Sounds like huge overkill to me....

You gonna be just fine with 30 or lets say 40 if you do not plan to put life stock there...

Also you save lots of cash too


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## Victor (30 Jul 2014)

It's because I want the same amount of CO2 that we find in the atmosfhere. I want to see what happens to underwater plants at this level of CO2. I also have some plants with transparent leaves. With CO2 at 50 ppm the leaves don't have improved.


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## Vazkez (30 Jul 2014)

well kk I am sure some one with more knowledge will pop up. 
However I can be mistaken but I think it will not do much diferences as 50 should be more than enough.


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## Victor (30 Jul 2014)

Yes, I'm a bit confused too. Let's wait for more advices


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## Andy Thurston (30 Jul 2014)

No livestock...
Nuke away make sure flow, macro and micro are good and if your plants still look a little unhealthy reduce the lighting.
I think you would be pretty lucky to achieve 400ppm though. When i started my tank i lowered ph as much as i could. I only got it to 4.8 and that was in fairly soft water


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## Victor (30 Jul 2014)

Big clown said:


> I only got it to 4.8 and that was in fairly soft water


 My water is very soft too. I think I'll also reach this ph


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## Victor (30 Jul 2014)

I'm afraid that a ph lower than 5,0 could kill my bacterial colony. Could this really happens?


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## Andy Thurston (30 Jul 2014)

I'm not sure but i think i've read a post by clive, saying it wouldn't do any harm unless livestock was present.
My fish/shrimp seem fairly happy now at ph 5.9 from 7.4


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## foxfish (30 Jul 2014)

How on earth do you intend to get that much gas in your tank - dose it have a sealed bolted down top or some specialised  equipment?


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## Victor (30 Jul 2014)

I know that I maybe never reach this mark. I just want to get close it. My concern is about a very acid ph.


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## Nils Axelsson (30 Jul 2014)

Victor said:


> It's because I want the same amount of CO2 that we find in the atmosfhere. I want to see what happens to underwater plants at this level of CO2. I also have some plants with transparent leaves. With CO2 at 50 ppm the leaves don't have improved.



I'm far from an expert at this but I read about this not long ago on a swedish forum. It was a thread about a CO2 meter presented on kickstarter. And a discussion about the difference in ppm in air vs ppm in water occured. Therefore one person asked Tim, who started the Kickastarter-project.

Again, the question was something about ppm in air vs ppm in water and the difference or if it is the same thing. This is the answer:

"Tim Burton says:
Hi Martin, thanks for your email. There's actually a yes-and-no answer to
your question, and I have to explain it first by saying that there are two
distinct types of units called 'ppm' (parts per million); ppm can refer to
parts per million by volume or parts per million by weight(or mass). The
ppm we tend to use in planted aquarium is ppmw, and the ones used by
atmospheric scientists is ppmv. So, when we say we ~30 ppm of CO2 in our
aquarium, this unit is not the same (and not easily convertible to) the 395
to 405 ppmv that atmospheric scientists are quoting. In order to equate
these, need to know temperature and pressure of the atmosphere at the point
we are measuring. So, as a general idea, at sea level for our aquariums, a
~400 ppmv of atmospheric CO2 is roughly the same as 3 ppmw inside our
aquarium. So to finally answer your question, yes the variance of +- 5
ppmv atmospheric CO2 will change the calibration of the CO2 sensor
slightly, but that will only amount to be ~0.1 ppmw of CO2 as measured in
our aquarium. Considering that we change the CO2 in our tanks by 20-30 ppm
over a 24 hour period, I feel that this is an acceptable level of
inaccuracy."

http://www.plantswap.se/viewtopic.php?f=12&t=18654&start=10


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## ceg4048 (30 Jul 2014)

Add as much CO2 as you want and just get on with it. These are all fantasy numbers anyway. Nobody really knows what concentration levels are in the tank and it's not the same from point to point in the tank anyway. What the plants see are about 10% of what you imagine is there.

Just know that if you need to go over the top with your injection to solve deficiency problems then it probably means you have either too much light or poor flow/distribution, or both, which is something you'll have to address eventually when you want to add fish. OTT CO2 injection is great for tank startup, but eventually you'll need to find a middle ground.

Cheers,


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## Victor (30 Jul 2014)

ceg4048 said:


> Just know that if you need to go over the top with your injection to solve deficiency problems then it probably means you have either too much light or poor flow/distribution, or both, which is something you'll have to address eventually when you want to add fish. OTT CO2 injection is great for tank startup, but eventually you'll need to find a middle ground.


 I think the problem is just poor CO2. My flow and distribution is very good (20 x tank volume per hour passing by the filters and pumps and very well distributed by all tank lengh). I'm using only 2x 30wT8 tubes with reflectors over my 300 L tank. The tubes aren't side by side. Thank you, Ceg!


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## Victor (31 Jul 2014)

Ah, just one more doubt. There is any difference to plants to keep CO2 at 30 ppm or 100 ppm? At 100 ppm they will grow more healthier and lush than 30 ppm?


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## ceg4048 (1 Aug 2014)

Higher CO2 concentration levels allow the plant to put on more weight faster, and it allows you to use higher levels of lighting, which will improve the rate of growth, however there are drawbacks. As the CO2 concentration level increases the CO2 uptake efficiency of the plant DECREASES. That's because the plant knows that it can now allocate more of it's resources to other things, such as pigmentation, Nitrogen uptake and so forth. The CO2 uptake system is a very expensive, high maintenance system.

Having purposely reduced the robustness of it's own CO2 uptake system, ironically, the plant now becomes more susceptible to CO2 shortfalls. So when the tank is at very high CO2 levels, even minor downward fluctuations of the CO2 concentration will have a major negative effect on plant health, exactly because the CO2 uptake system has become flimsy. At lower CO2 concentration levels, the plants knows that it must dedicate a large proportion of it's energy to ensuring CO2 uptake, so at low levels it can more easily tolerate larger percentage gaps, drops and fluctuations.

CO2 therefore, is as Barr described it - a narcotic; the more you feed them the more you'll need to feed them.

This is exactly why people who decide to add CO2 to their tanks immediately begin to suffer CO2 related deficiency syndromes. Then they go into denial because they think: "but I'm adding CO2 now so how can melting and hair algae possibly be due to CO2 deficiency?"

Cheers,


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## Victor (1 Aug 2014)

ceg4048 said:


> Then they go into denial because they think: "but I'm adding CO2 now so how can melting and hair algae possibly be due to CO2 deficienc


 That makes sense. Ceg, in your opinion, do you think it's better I keep high CO2 levels in quite low light tank? I've reach the mark of 100 ppm o CO2 or even more. I'm using 2 drop Checkers, one at 8,5 ºdh and another with 20,5 °dh. The first one is yellow and the second is lime green! Do you think I'm exaggerating in CO2? Should I increase my light to compensate this huge CO2 level? I'm using a line composed of two T8 tubes that extends by all tank lenght. Each tube has 30 w and I'm using good reflectors over each one. My tank has 300 L (200 cm lenght x 40 cm witdh x 45 cm height) and I have a very good flow. I'm really confused now. I'll wait for more advices. Thank you so much!


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## foxfish (1 Aug 2014)

Hi Ceg that is interesting... so on that basis if one had an established 200l, low tech tank, with low lighting & then decided to add co2 at a very low rate, let just say 1bps, it would in fact cause problems rather than benefits?


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## ceg4048 (1 Aug 2014)

foxfish said:


> Hi Ceg that is interesting... so on that basis if one had an established 200l, low tech tank, with low lighting & then decided to add co2 at a very low rate, let just say 1bps, it would in fact cause problems rather than benefits?


Well remember that I did not say that one bad thing happens to the exclusion of the good thing. I said that both good and bad things happen. How good the good thing is compared to how bad the bad thing is determines failure or success.

The difference in CO2 concentration level from non-injection to very low injection is small. So both the good and bad changes that happen are small. They may be small enough that you notice one thing and ignore the other. CO2 addition is always a help. As I mentioned earlier, increased CO2 reduces the CO2 uptake ability but it also INCREASES the efficiency of the Nitrogen uptake and assimilation mechanisms. Nitrogen is an important component of Chlorophyll and so more CO2 enables the plant to make better use of lower light.

The Matrix teaches us that when we decide to add CO2 to a tank then it is mandatory to use more light,when in fact plants are better able to use LESS light.

So, in the scenario given, the low lighting is likely NOT be an issue, the CO2 increase is likely to improve growth rate by a small amount and the susceptibility to poorly delivered 1BPS is likely to increase a small amount.

Tally the above and imagine what the likely outcome  overall is - good or bad?

But that's not the end of the story. In our initial analysis we assume that the 1BPS is applied competently, but what if there is incompetence? What is the probability of  incompetence? I suggest a 95.9% incompetence factor. We also assume that Nitrogen dosing is accomplished to take advantage of improved uptake efficiency. What are the probability of test kits being used to determine Nitrogen levels I suggest a 80% test kit lover factor...and if the user suffers symptoms of Nitrate paranoia? I suggest a 98% Nitrogen paranoid delusional syndrome (NPDS).

Now, re-evaluate the scenario for probable outcome.......problems or benefits?




Victor said:


> That makes sense. Ceg, in your opinion, do you think it's better I keep high CO2 levels in quite low light tank? I've reach the mark of 100 ppm o CO2 or even more. I'm using 2 drop Checkers, one at 8,5 ºdh and another with 20,5 °dh. The first one is yellow and the second is lime green! Do you think I'm exaggerating in CO2?


I really can't say for sure mate. What I can say for sure is that even if you measured 100ppm with your DC the plants probably were only seeing 10ppm. The more CO2 you add to the tank the faster it escapes and it is never the same at any two points in the tank. So the numbers look cool and no doubt the calculations were performed accurately, but in the end it doesn't mean much. If your distribution is excellent then the plants will see a high percentage than if you have poo distribution.

I don't try to drive my tanks to ppm numbers because they are an illusion. Look at CO2 as a system, not a number. If my plants were suffering a CO2 deficiency syndrome I would immediately look at reducing the light increasing CO2 and improving flow distribution. As I mentioned before, when you have fish in the tank you will have to be a lot more careful how you increase the injection. It's fine now without fish but you need to also consider that if you have high injection rates and are still suffer melting then flow/distribution and gas dissolution methods need to be investigated.



Victor said:


> That makes sense. Ceg, in your opinion, do you think it's better I keep high CO2 levels in quite low light tank?


Sure, why not? But as I mentioned to foxfish if you don't add the high CO2 properly you can have problems, probably not as severe as if the light were high though. CO2 is good for any light.



Victor said:


> Should I increase my light to compensate this huge CO2 level?


Only if you want to have more problems. Adding more light never compensates for anything.

I have no idea without seeing images of the configuration and getting more data, but generally I'd say it's probable your distribution is suspect.

Cheers,


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## Victor (2 Aug 2014)

ceg4048 said:


> The Matrix teaches us that when we decide to add CO2 to a tank then it is mandatory to use more light,when in fact plants are better able to use LESS light.


Perfect! Ceg, I really love yours explanations . Take a look at this video (it's from my tank). As you can see my plants are a bit fragile. My hemianthus micranthemoides, rotala green, didiplis diandra and glossos are growing mainly upwards. I've increase the CO2 level 2 days ago. What do you think about the flow? And about CO2 diffusion? Thank you.


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## ceg4048 (2 Aug 2014)

Hi Victor,
                That looks better than I thought it might. It looks like flow is moving across the bottom towards the back, but what I don't like is the diffuser. That's just not  a very good device at all. You would be better off porting the gas directly into the filter inlet or using some kind of inline device. Prune the plants, pull out the bottom halves and replant the tops.

Cheers,


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## Victor (2 Aug 2014)

ceg4048 said:


> Hi Victor,
> That looks better than I thought it might. It looks like flow is moving across the bottom towards the back, but what I don't like is the diffuser. That's just not  a very good device at all. You would be better off porting the gas directly into the filter inlet or using some kind of inline device. Prune the plants, pull out the bottom halves and replant the tops.
> 
> Cheers,


Alright! The diffuser is a JBL pro flora Taifun Reactor. There are 3 of them in my tank. It increases the contact time of CO2 bubbles with the water because it has a CO2 path in spiral. Each reactor that I have is roughly 25 cm tall. That means that each CO2 bubble will travel about 1,2 m in the water until it reaches the surface! These reactors are very efficients. Check the video below and you'll see that CO2 bubbles will become smaller as they approach of the reactor top. Even then, do you think a inline device will work better? I could to it . Thank you again.


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## foxfish (2 Aug 2014)

I have used similar reactors before but they will not be as efficient  as an inline reactor that is connected directly into the main circulation flow.


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## Victor (3 Aug 2014)

So, my problem is actually the CO2 diffusion? That's it?


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## ceg4048 (4 Aug 2014)

As I mentioned, before you spend money, remove the devices and port the gas directly into the filter intake(s). Then check the pH profile and, most importantly, see if the plants respond.

Cheers,


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## Victor (4 Aug 2014)

ceg4048 said:


> As I mentioned, before you spend money, remove the devices and port the gas directly into the filter intake(s). Then check the pH profile and, most importantly, see if the plants respond.
> 
> Cheers,


 Alright, I'll do it. I'll I also will buy some porous stones to put in the power heads pipes to help the CO2 diffusion. What do you think about? The stone is this one: http://produto.mercadolivre.com.br/...pequen-cermica-55-x-15cm-micro-bolhas-2pc-_JM it produces micro bubbles. Thank you.


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## ceg4048 (4 Aug 2014)

Well to tell the truth Victor, I'm very confused as to your plumbing. Are you saying that the powerhead output is ported into a spraybar? I thought your spraybar was connected to the output of your filter. Your video did not focus on the plumbing so that's not clear at all. If the powerheads are not connected to the spraybar then there is no need for stones. If they are connected to a spraybar then it might help when the powerhead sucks the CO2 bubbles in. I just not understanding the setup at all. Maybe a sketch or a schematic might help to clarify, Sorry...

Cheers,


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## Victor (4 Aug 2014)

ceg4048 said:


> Are you saying that the powerhead output is ported into a spraybar?


 Yes, there are 3 powerheads connected to a spraybar (the brown pipe). Look again the video, it's a few hidden but in some parts you can see the brown pipe at the top part of the tank. The 2 green spraybars is from the filters. Got it?


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## ceg4048 (4 Aug 2014)

OK, well ideally the gas should be ported into the filter inlet, not into the powerheads, but this is very strange because it appears that the green spraybar is on very short compared to the gray spraybar - and it's mounted on the end.

I guess you'll have to try different combinations of porting gas into both the filters and the powerhead inlets. The money that you spent buying 3 of those loco ladders and 3 powerheads would have been better spent just buying a more powerful filter. There would be less junk inside the tank and better CO2 dissolution through the gray spraybar. You wouldn't even need the green piece.

Yes, this is all very strange, but I'm sure you did the best you could with what you had - and the flow does look OK in that video. As long as the water jets come out of the holes in a straight line towards the front glass then all is good, but I suspect that you might just be spitting out bubbles from the gray spraybar if you inject through the powerheads but it will be better than those ladders.

Cheers,


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## Victor (4 Aug 2014)

ceg4048 said:


> OK, well ideally the gas should be ported into the filter inlet, not into the powerheads, but this is very strange because it appears that the green spraybar is on very short compared to the gray spraybar - and it's mounted on the end.


Yes, the green spraybars is really very short. The are 2 in each corner of the tank. The flow is made mainly by the powerheads. I did a scheme here: https://imageshack.com/i/hjfWZcs7p .The blue crosses are the locals where I'll drill the pipe to put the CO2 hoses with the porous stones that will stay inside the gray pipe. There are two stoppers that separate the flow of each powerhead inside the spraybar. Forget about the CO2 ladder in the image, this is a old picture.


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## ceg4048 (4 Aug 2014)

Yeah, OK, I was too nervous to ask how you prevented the powerhead flows from interfering with each other but the stopper is a good idea. I realize you're getting rid of the ladders but just for future reference, you might have had better luck with them if you had ported their output into the pumps instead of just letting the gas escape out the top of the tank.

Cheers,


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## Victor (4 Aug 2014)

ceg4048 said:


> I realize you're getting rid of the ladders but just for future reference, you might have had better luck with them if you had ported their output into the pumps instead of just letting the gas escape out the top of the tank.


 Yes, I've thought about this but I was not able to do the powerheads suck the gas on the ladder top . But it doesn't matter now. I'll do the inline diffusion


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