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Providing 'just enough' CO2

Courtneybst

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Hey guys,

I've been thinking a lot recently about getting a pressurised CO2 system and was wondering if it's possible to provide just enough CO2 so the plants are healthy and not melting back?

My thought process is that I want the plants to be healthy but I don't want to constantly trimming plants either. I know low CO2 can be an issue but if I currently have no CO2 (or just what's available from the atmosphere), isn't a little bit of CO2 better than nothing?

I would be looking at an in-line diffuser because of the size of my tank.
 

ScareCrow

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This is something I'm also planning on doing as I don't really like dosing liquid CO2. I have a couple of plants that are right on the edge of needing/not needing CO2 but as I have hard water they won't survive without a little help. I've tried using rainwater to soften the water and also having a siesta period to make the most of the available CO2. I think that the siesta period has shown the most benefit and is nice because I can view the tank morning and evening. There are a couple of posts on here about using lower than the normal 30ppm CO2 concentration:

15 ppm co2 goal

CO2 in low tech?
 
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isn't a little bit of CO2 better than nothing?
Hi, yeah just a little bit of co2 is definitely better than nothing, what the plants need is carbon and they can get it from dissolved organic carbon in the water or from co2 that is absorbed in to the water from the atmosphere/fish respiration/bacteria. Both are very limited though and in short supply. A lot depends on which types of plant you're trying to grow so plant selection is important. Tropica uses the easy/medium/hard categorisation, generally speaking keeping the easy plants means they will do ok without injecting co2 although they will do a bit better by adding co2.
Adding medium and upwards plants requires higher lighting which then pushes up the need for more co2 if you turn up the lights which isn't going to get fulfilled by background carbon. The upside/downside to this is plants will inevitably grow quicker and you will do more trimming. Ultimately you need to match the growth rates the light is producing with ferts and co2 so nothing is missing as the plants grow. The co2 will always be the one that runs out first in a non co2 tank because we can easily add more fert as required.

Adding a touch more co2 will always be beneficial, the issues people experience generally come from not getting the co2 stable and everywhere in the tank it needs to be but they are usually pushing hard on the lights. Not going over the top with lighting is a bit more forgiving if you don't get it right.
 
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Best analogy for plant growth is building a wall, you need a brick/macros and mortar sand/micros and cement/co2 as the plant grows it needs all three at the pace you build driven by light. As light increases you build the wall faster, the secret is to never run out of any of the three, adding a touch more co2 just makes sure you don't run out of that which is the easiest to run out of.
 
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Your only worry is that plants get addicted to co2 in so far as plants will adapt to the amount they have around them, if you take it away from them after they've adapted to the new higher levels they suffer. That's why it important to keep stable levels at all times. It can be something as simple as a plant that was getting plenty of co2 now getting flow to it blocked by some other plants that have grew quite bushy in the way of the flow and that plant fails which leaves you wondering how come it's worse now that I'm adding co2? Bit of a PITA really but if that's the route you want to go down these are the things that you need to take into account. It can be a bit of a minefield which is why I don't bother with it any more and just stick to plants that shouldn't need it.

You could try just adding some of the easy carbo products that are out there (Controversial) which adds a little more carbon. I've been using Microbe-Lift Bio co2 which you can get from Maidenhead Aquatics which adds beneficial organic carbon but doesn't contain the supposedly dangerous chemicals like in other Liquid Carbon products. My plants do fine but I manage the lighting and stick to the easy range of plants.
 

Courtneybst

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Your only worry is that plants get addicted to co2 in so far as plants will adapt to the amount they have around them, if you take it away from them after they've adapted to the new higher levels they suffer. That's why it important to keep stable levels at all times. It can be something as simple as a plant that was getting plenty of co2 now getting flow to it blocked by some other plants that have grew quite bushy in the way of the flow and that plant fails which leaves you wondering how come it's worse now that I'm adding co2? Bit of a PITA really but if that's the route you want to go down these are the things that you need to take into account. It can be a bit of a minefield which is why I don't bother with it any more and just stick to plants that shouldn't need it.

You could try just adding some of the easy carbo products that are out there (Controversial) which adds a little more carbon. I've been using Microbe-Lift Bio co2 which you can get from Maidenhead Aquatics which adds beneficial organic carbon but doesn't contain the supposedly dangerous chemicals like in other Liquid Carbon products. My plants do fine but I manage the lighting and stick to the easy range of plants.

This is an interesting point and something I definitely didn't consider!

Another point on the liquid carbon side of things; In my old scape I used liquid carbon at double strength and I actually had pretty good growth and a full lush carpet. It's hard to tell if it worked because I was adding that or because of another factor? I was also dosing full EI at the time. I still have a full bottle of Easy Carbo and keep getting tempted to use it but I'm unsure. I also noticed that when I slacked on Easy Carbo I would get BBA so that's why I stopped using it altogether.

What are your thoughts?
 
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I also noticed that when I slacked on Easy Carbo I would get BBA so that's why I stopped using it altogether.
Stability is key, I would use it if you saw good results, LC products add a touch extra carbon as well as a powerful algaecide and you have a lot of control with the dosing whereas co2 is like rubbing your belly while patting your head. The stuff I use doesn't contain the powerful algaecide which is the bit people worry about. It does add humic acids and tannins though so regardless it's a beneficial product. Not saying that if I didn't use it things would be any worse but I'm getting decent results. You shouldn't need to be dosing EI levels of ferts either I would guess. If you were in a position to need EI ferts (The theoretical maximum plants could ever need) You %100 percent would have ran out of co2 at some point.
You only have to provide slightly more of everything than the plants need to prevent any limiting factors. What's your current set up like?
 
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and before I get jumped on by the LC police, for clarity LC is one chemical with the two properties, adds a little carbon as well as an algaecide so it's the one chemical people worry about because it is toxic to humans which not may be how I explained that clearly :D
 

Courtneybst

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Stability is key, I would use it if you saw good results, LC products add a touch extra carbon as well as a powerful algaecide and you have a lot of control with the dosing whereas co2 is like rubbing your belly while patting your head. The stuff I use doesn't contain the powerful algaecide which is the bit people worry about. It does add humic acids and tannins though so regardless it's a beneficial product. Not saying that if I didn't use it things would be any worse but I'm getting decent results. You shouldn't need to be dosing EI levels of ferts either I would guess. If you were in a position to need EI ferts (The theoretical maximum plants could ever need) You %100 percent would have ran out of co2 at some point.
You only have to provide slightly more of everything than the plants need to prevent any limiting factors. What's your current set up like?

Oh yeah for sure I was dosing way more than I needed back then. I now only dose 1/3 of the EI and I've turned one of my T5 units off so the lighting is essentially 50%. I'm definitely noticing A LOT less algae growth. This scape is literally waiting to be torn down as soon as plant deliveries arrive though so the plant mass is much lower than I'd like and the substrate has turned to mud which is further exacerbating any algae issues.

The setup though;

4 x 54w T5 bulbs (now only using 2 - the unit only allows 2 or 4)

Cal Aqua Labs Black Earth

120cm x 50cm x 66cm

1/3 EI dosing

I'm hoping once I bump the plant mass back up and refresh the substrate it should be ok, and I can increase or decrease accordingly as the plants grow.
 
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Courtneybst

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Which would be very difficult to achieve without something "extra" IMO

658062a41bde8a93eb80b9204cc92b05.jpg


This was the previous setup I was referring to.
 
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And your complaint is what exactly again :D:thumbup: That's a nice setup. Only thing I would say is that's quite a large tank so LC may not be cost effective depending on the depth of your pockets. However...... If you were going down the route of co2 you really need to get your flow and distribution down pat, even more difficult in big tanks!
If it were me and I was going down the co2 route again, what I would do is firstly start at the ground up with a decent nutritious substrate. Plant as much as you can from the off with easy plants which you already have in a low lighting setting. Then slowly build co2 until I felt I could move on to more demanding plants and up my lighting.

There's many failures in here with people trying co2 for the first time in an immature tank where plants haven't got a foot hold yet.
 

Courtneybst

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And your complaint is what exactly again :D:thumbup: That's a nice setup. Only thing I would say is that's quite a large tank so LC may not be cost effective depending on the depth of your pockets. However...... If you were going down the route of co2 you really need to get your flow and distribution down pat, even more difficult in big tanks!
If it were me and I was going down the co2 route again, what I would do is firstly start at the ground up with a decent nutritious substrate. Plant as much as you can from the off with easy plants which you already have in a low lighting setting. Then slowly build co2 until I felt I could move on to more demanding plants and up my lighting.

There's many failures in here with people trying co2 for the first time in an immature tank where plants haven't got a foot hold yet.

Haha thank you, I'll definitely be planting heavy again.

I think ultimately I will go with CO2 in the long run and I'll echo your words in my brain as I'm setting it up.
 
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Get it whacked in a journal once all your stuff has turned up mate. Be good to watch it develop, I'll keep an eye out for it.
 

dw1305

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Hi all,
isn't a little bit of CO2 better than nothing?
The upside/downside to this is plants will inevitably grow quicker and you will do more trimming. Ultimately you need to match the growth rates the light is producing with ferts and co2 so nothing is missing as the plants grow. The co2 will always be the one that runs out first in a non co2 tank because we can easily add more fert as required.
That one.

cheers Darrel
 

tiger15

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Hi, yeah just a little bit of co2 is definitely better than nothing, what the plants need is carbon and they can get it from dissolved organic carbon in the water or from co2 that is absorbed in to the water from the atmosphere/fish respiration/bacteria.
I would like to see citation that plants can uptake dissolved organic carbon. I always read that DOC is a cause of algae, not a source of carbon.

To answer the OP original question, you can grow healthy plants with CO2 injection without attaining 30ppm. I grow easy plants in a 75 gal and used up a 10lb CO2 tank in a year. I provide 4 hour split photo periods and the peak CO2 is only around 15 to 20 ppm. My plants are healthy and free of algae, so I wonder who and why it is necessary to set 30 ppm as the goal. Most natural water don’t get that high CO2, and water in equilibrium with the atmosphere gets only 2 to 3 ppm CO2, so some elevated CO2 is already a significant improvement.

LC is a different subject of discussion with many threads on it. I dose LC at high initial rate after weekly WC to control algae. I believe LC is an effective Algaecide but doubt that it is an effective source of carbon given the daily dosage rate is only 0.4 ppm glutaldehyde per Seachem instruction. So even if we assume all 0.4 ppm is convertable to carbon, the quantity is insignificant.
 

Courtneybst

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I would like to see citation that plants can uptake dissolved organic carbon. I always read that DOC is a cause of algae, not a source of carbon.

To answer the OP original question, you can grow healthy plants with CO2 injection without attaining 30ppm. I grow easy plants in a 75 gal and used up a 10lb CO2 tank in a year. I provide 4 hour split photo periods and the peak CO2 is only around 15 to 20 ppm. My plants are healthy and free of algae, so I wonder who and why it is necessary to set 30 ppm as the goal. Most natural water don’t get that high CO2, and water in equilibrium with the atmosphere gets only 2 to 3 ppm CO2, so some elevated CO2 is already a significant improvement.

LC is a different subject of discussion with many threads on it. I dose LC at high initial rate after weekly WC to control algae. I believe LC is an effective Algaecide but doubt that it is an effective source of carbon given the daily dosage rate is only 0.4 ppm glutaldehyde per Seachem instruction. So even if we assume all 0.4 ppm is convertable to carbon, the quantity is insignificant.

Sweet! This is exactly the kind of thing I was hoping to achieve.
 
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I would like to see citation that plants can uptake dissolved organic carbon. I always read that DOC is a cause of algae, not a source of carbon.
My understanding of this from somewhere I read was that doc from tannin and humid acids binds heavy metals and makes nutrients available to plants and creates co2 as it is broken down.
In the case of waste and by products other waste would enter the column which causes algae. My guess would be that the bottle of stuff I have contains the beneficial parts but without all the other crap that would come from decomposition.
But that's just a guess, the rest is above my pay grade when it comes to the technical side.
In my case with extremely soft water and soft water species it allows me to get some tannins and humics said to be beneficial to the fish without having rotting leaves in the bottom of my tank although to be fair I do both for the shrimp to graze on.
I, like the op are probably running right on the edge of what's possible without co2, my plants do fine and it's hard to say whether the product contributes without stopping and seeing what happens but that would seem to be an experiment in futility. If it's not broke don't try and fix it right.

We all have different agendas just co2 isn't mine for now, I can just do without the extra layer of complication in my already busy life.
I'm not against lc either I just see it as something else I need to buy and remember to dose. Although putting powerful algaecides in a tank doesn't sit that well for some reason when I'm trying to get results with what nature gave me other than obviously a light,heater and a filter.
 
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