# CO2 and Plants



## Fish on the Mind (Feb 9, 2012)

How many fish would be needed to off set the need of CO2 the plants would need. In my case a 30 gallon lightly planted tank.


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## george (Apr 11, 2009)

I do not think you will can have enough fishes to offset the CO2 the plants will need. There is a variable though. Are you thinking of low or high CO2? Because there is CO2 in the water anyway from the fishes even if you do not have any additional source of CO2.


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## Will (Jul 24, 2008)

In tanks without CO2 input, in which I have placed a CO2 Drop checker, I've never even seen a registered reading of CO2, so either it is so minute it is not measured properly via this method or that the plants are consuming it faster than the fish produces it or the water absorbs it from the atmostphere.


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## Fish on the Mind (Feb 9, 2012)

I believe it would be low CO2. I would prefer to find an amount of fish that would make enough CO2 for the plants to survive well enough. Than making an external source of putting in CO2.


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## solarz (Aug 31, 2010)

Fish on the Mind said:


> I believe it would be low CO2. I would prefer to find an amount of fish that would make enough CO2 for the plants to survive well enough. Than making an external source of putting in CO2.


It doesn't work that way. Plants don't need CO2 injection to survive, but CO2 injection makes plants grow much faster. The advantage of faster growing plants is to have faster nitrate uptake. Putting in more fish would simply be counter productive.


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## Will (Jul 24, 2008)

I would think you'd have to a still water tank stocked like this (photo below) to provide enough CO2 to keep it between 20-40ppm in a densely planted tank. Might be talking out of my ass here, but I just don't see stocking enough small tropical fish into a tank to provide CO2 at comparable levels. Not to mention at the level you'd need to stock to get that much CO2 you would equally deplete the O2 levels in the tank. On top of that you would have to balance the amount of light intensity and plant mass to ensure not only that the plants are photosynthesizing at a fast enough rate, but also absorbing that much CO2, and equally expelling enough O2 through pearling to make the O2->CO2->O2 cycle sustainable.


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## Fish on the Mind (Feb 9, 2012)

Ok so what I think of this would be that the plants just use the amount of CO2 That is in The tank. the more CO2 in the tank ( to a degree) the faster the plants would be able to use and therefor grow ( provided there is other needed elements) ? 

So I don't really have to worry about putting added CO2 unless I want the plants to thrive essentially.


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## solarz (Aug 31, 2010)

Fish on the Mind said:


> Ok so what I think of this would be that the plants just use the amount of CO2 That is in The tank. the more CO2 in the tank ( to a degree) the faster the plants would be able to use and therefor grow ( provided there is other needed elements) ?
> 
> So I don't really have to worry about putting added CO2 unless I want the plants to thrive essentially.


Put simply, CO2 make plants grow faster. Faster growing plants have the following advantages:

1- Fills up tank with lush growth more quickly
2- Absorbs ammonia or nitrates more quickly, allowing for a higher stocking density
3- Help control algae

Also note that CO2 and Light must be balanced. Too much light + not enough CO2 = Algae problems. Too much CO2 + not enough light = wasted CO2.


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## Fish on the Mind (Feb 9, 2012)

Ok thanks for the help. Got another question what is a cheap cheap way to make a CO2 input system.


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## Will (Jul 24, 2008)

The cheapest I know of:
HOW TO DIY CO2 For Planted Aquariums 
HOW TO DIFFUSE DIY CO2 into an Aquaclear Filter 
Unfortunately there are no controls for a Sugar Yeast CO2 Reactor, no way to make minute by minute adjustments, and no efficient way to turn it off at night. And so if you nuke your tank it may very well end up being the most expensive method of CO2 injection.


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## solarz (Aug 31, 2010)

DIY CO2 is easy and safe. For a 30-gal tank, unless you seal off the top, you'll never have to worry about overdosing on CO2.

All you need is the following:

- A drill
- A 2L soda bottle with cap
- a length of air tube
- a plier
- a pair of scissors
- a disposable chopstick
- some active yeast
- lots of sugar
- a spare soda bottle cap

Steps:

1. drill a hole that is slightly smaller than the air tube on the soda bottle cap

2. cut the air tube at an angle, so that it ends in a pointy bit; push the pointy bit into the cap and use the pliers to pull about 2" of the tube into the cap; the air tube should not be sticking out of the cap and tightly wedged;

3. if the soda bottle is dirty, wash it clean; put ~2 cups of sugar + 1 teaspoon of yeast into the bottle, fill halfway with lukewarm water (the water should feel neither cold nor warm), close it with the undrilled cap, and shake the mixture well; remove the undrilled cap and fill the rest of the bottle up with lukewarm water until it's about 4" from the top of the bottle

4. put the cap with the air tube onto the bottle, and screw it in tightly

5. stick the disposable chopstick into the other end of the air tube, tie something heavy onto it so that it sinks, then put it into the tank

If you mixed up the sugar and yeast well, you should start seeing bubbles in an hour or two.


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## rubadub (Sep 12, 2010)

there is the DIY paintball setup

i have a ASA with a ****** Needlevalve on it that i could sell
u'd still have to buy the paintball tank tho

and u wont have a regulator or solenid valve

there are many choices out there for ya


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## Will (Jul 24, 2008)

I disagree, you can gas your fish overnight if your not careful with DIY Sugar+Yeast.
Another danger is fluctuating co2 levels and potential BBA algae. 
Doesn't mean it's not a cheap solution.


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## rubadub (Sep 12, 2010)

i used to run my paintball setup 24/7 lol
i had my airpump on a timer tho
so yes i did waste a lot of co2 lol
but hell a 20oz paintball tank used to last me 4 months or so


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## charlie1 (Dec 1, 2011)

solarz said:


> It doesn't work that way. Plants don't need CO2 injection to survive, but CO2 injection makes plants grow much faster. The advantage of faster growing plants is to have faster nitrate uptake. Putting in more fish would simply be counter productive.


Not accurate
Plant tissue is about 60% carbon - building block of plants,very much like calcium is the building block of bone growth.
CO2 is only a transport for carbon
No carbon - plants don`t grow healthy -hence algae will love you since the plants are not eating so the food(nutrients) is there for algae spores to devour.Very much like a growing child with no calcium their bones don`t develop & you guessed it brittle , deformity etc.
Hope that helps

P.S. @OP if you don't want to inject CO2 or supplement carbon, try looking at the reverse of the way you are thinking-think low light simple low light plants, low plant mass high fish load, *maybe* then you might be able to self sustain carbon from fish respiration etc.


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## Fish on the Mind (Feb 9, 2012)

Okay so can u just take out the tube or plug it for the night?That way it would be a little more safer.


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## solarz (Aug 31, 2010)

charlie1 said:


> Not accurate
> Plant tissue is about 60% carbon - building block of plants,very much like calcium is the building block of bone growth.
> CO2 is only a transport for carbon
> No carbon - plants don`t grow healthy -hence algae will love you since the plants are not eating so the food(nutrients) is there for algae spores to devour.Very much like a growing child with no calcium their bones don`t develop & you guessed it brittle , deformity etc.
> ...


CO2 is not a transport for carbon, CO2 the *source* of the carbon in plants, more specifically in the form of C6H12O6, aka sugar.

One of the advantages of live plants in a tank is their ability to absorb toxins such as ammonia and nitrates. Fish produce far more ammonia than CO2, relative to plant uptake, which means that adding more fish will increase the bioload much faster than plant growth, effectively negating one important advantage of live plants.


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## charlie1 (Dec 1, 2011)

Fish on the Mind said:


> Okay so can u just take out the tube or plug it for the night?That way it would be a little more safer.


Can you eloborate some more , not quite sure what you are asking.
Regards


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## charlie1 (Dec 1, 2011)

solarz said:


> CO2 is not a transport for carbon, CO2 the *source* of the carbon in plants, more specifically in the form of C6H12O6, aka sugar.
> 
> One of the advantages of live plants in a tank is their ability to absorb toxins such as ammonia and nitrates. Fish produce far more ammonia than CO2, relative to plant uptake, which means that adding more fish will increase the bioload much faster than plant growth, effectively negating one important advantage of live plants.


Perhaps i should have been more specfic to avoid the technical sorts.
CO 2 gas is just one of the transport of getting carbon into the water column .
Not quite sure this thread as per OP was dealing with the advantages or disadvantages of live plants but perhaps i missed it.
Regards


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## solarz (Aug 31, 2010)

Fish on the Mind said:


> Okay so can u just take out the tube or plug it for the night?That way it would be a little more safer.


I would not worry about it at all. I leave my DIY CO2 in my 20 gallon tank all the time. My tank water pH is 8. Usually the CO2 is not even enough to change that pH. The only time the CO2 was strong enough to drop my water pH from 8 to 7 was when I put in triple the amount of yeast than I should have, but even then I left it in overnight and the fish were fine.

Do some research on DIY CO2 and you'll have a better understanding of what's involved.


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## charlie1 (Dec 1, 2011)

Will said:


> I disagree, you can gas your fish overnight if your not careful with DIY Sugar+Yeast.
> Another danger is fluctuating co2 levels and potential BBA algae.
> Doesn't mean it's not a cheap solution.


 i disagree, the likely hood of gassing fish with DIY sugar & yeast generated CO2 is next to nil, unless you go to painstaking efforts to prove it , in which case you would be negating the only pro of it - cost.
I agree the fluctuation of co2 levels from start up to mid life & end of energy sugar) consumption by the yeast will be an accelerator of algae issues.
Regards


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## Fish on the Mind (Feb 9, 2012)

Of coarse I will do more research on DIY CO2 for sure. Thanks for all the help. Just got a few more questions you guy will prob know the answer to. how would you gas the fish out; Put too much of the mixture in by up sizing everything?. How long would DIY CO2 last for around 2 weeks?


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## solarz (Aug 31, 2010)

charlie1 said:


> i disagree, the likely hood of gassing fish with DIY sugar & yeast generated CO2 is next to nil, unless you go to painstaking efforts to prove it , in which case you would be negating the only pro of it - cost.
> I agree the fluctuation of co2 levels from start up to mid life & end of energy sugar) consumption by the yeast will be an accelerator of algae issues.
> Regards


From personal experience, I had far more algae problems *before* using DIY CO2 than after.

About 4 months after I first setup my 20-gal, I had a green hair algae outbreak. Everything in the tank was covered with it. I got 2 SAE, 6 amano shrimps, and started using yeast CO2. A few weeks later, the algae was gone.

The only algae problems i have now in that tank is green spot algae growing on the glass. I usually clean it off with a mag cleaner every 2 weeks or so.


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## Fish on the Mind (Feb 9, 2012)

Do Ottos not eat green algae? 
I also think I am going to give it a try


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## Fish on the Mind (Feb 9, 2012)

Oh and would it be safe to up the mix a little and use a 3 liter bottle? There is a 3 liter glass bottle here that would look good and would work.


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## solarz (Aug 31, 2010)

Fish on the Mind said:


> Of coarse I will do more research on DIY CO2 for sure. Thanks for all the help. Just got a few more questions you guy will prob know the answer to. how would you gas the fish out; Put too much of the mixture in by up sizing everything?. How long would DIY CO2 last for around 2 weeks?


The principle behind DIY CO2 is to generate CO2 with yeast and sugar. Yeast is a living organism that eats sugar and multiplies. The more yeast you have, the more CO2 you generate, but the faster the sugar becomes depleted. That's why you should stick to 1 teaspoon of yeast per 2L bottle of soda.

My bottles tend to last over a month, though certainly the final few weeks will produce less CO2, and you have to swirl it from time to time.


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## solarz (Aug 31, 2010)

Fish on the Mind said:


> Oh and would it be safe to up the mix a little and use a 3 liter bottle? There is a 3 liter glass bottle here that would look good and would work.


I would use 2L soda bottles. Those are designed to hold CO2. Using any other bottle will almost certainly result in leaks.


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## charlie1 (Dec 1, 2011)

OP all you want to know about DIY CO 2 & more
http://www.qsl.net/w2wdx/aquaria/diyco2.html
http://www.plantedtank.net/articles/DIY-Yeast-CO2/7/
Regards
P.S i once did 6 x 2 L pop bottles daisy chained on a 55 gallon & still could not generate enough CO 2 to sustain my 55 with 4x T12 tubes, don`t ask about the hassles for mixing & changing to try & keep it some what stable - when i switched to my first pressurized system( Milwaukee rig) i was in heaven.Do some digging on Champagne yeast or brewers yeast, helps a tad with sustained levels.
Regards


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## Fish on the Mind (Feb 9, 2012)

How long do co2 tanks last? For each size? Still debating to just go the system or not. Mostly is going to depend on cost right now.


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## charlie1 (Dec 1, 2011)

Fish on the Mind said:


> How long do co2 tanks last? For each size? Still debating to just go the system or not. Mostly is going to depend on cost right now.


 That would all depend on tank size , plant mass ,light intensity etc etc, there is no fixed table of 5 lb will last x months, that said i use to get around 8 mths on a 10 lb bottle on a 75 gallon with 3 xT5 HO 54 watt & heavy plant mass, don't expect to go below 200.00 on a commercial store bought rig with bottle new.
I sually direct folks on a tight budget & entry level rig to get the Milwaukee set up & used 10 lb bottle, if you search hard enough the Milwaukee rigs can be found for under a 100.00 new, not by any means a great rig, but it works with some tweaking & the customer service provided is second to none.
Regards


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## Fish on the Mind (Feb 9, 2012)

Okay so for the time being I have set up a DIY. Where could I go to price out a good complete CO2 system? Price is not going to be a huge issue because I am setting aside money for this so down the road I can get a good system.


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## Darkblade48 (Jan 28, 2008)

If you are handy (and patient to source the parts), then I would recommend that you try to source each part individually. This way, you can look for the cheapest deals, etc.

I managed to build a CO2 setup with a 10 pound cylinder, Victor dual stage regulator, Swagelok metering valve, JBJ bubble counter and Parker solenoid for 180 CAD.

As mentioned, commercial setups will cost more (and the CO2 cylinder would be an additional purchase on top of that).

If you might be interested in DIYing your own pressurized CO2 setup, please take a look at the article that I wrote (it is linked in my signature).


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## Jelly (Feb 28, 2012)

Finished my DIY set up with the chopstick about 2 hrs ago and it's working great!

I have the bubbles going up around the intake and whatever doesn't go up the intake is getting pushed back down into the water by the water flow.


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## Fish on the Mind (Feb 9, 2012)

Nice looks good with the chop stick making the small bubbles. I just used a air stone because there was no chop stick in the house. Did the same as you did and made it so the bubble went up into the intake pipe of the filter though. 

What size tank do u have jelly? Also how many bottles did you hook up in you tank?


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## Jelly (Feb 28, 2012)

I have a 20g and only used one bottle.

I had to put the pop bottle inside my stand and drill a hole out the back to run the line up to the tank because my 90 pound lab loves to chew plastic pop bottles.  

The plus is it's a pretty clean set up and my living room doesn't look like a meth lab.


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## FlyingHellFish (Mar 7, 2011)

Jelly said:


> Finished my DIY set up with the chopstick about 2 hrs ago and it's working great!
> 
> I have the bubbles going up around the intake and whatever doesn't go up the intake is getting pushed back down into the water by the water flow.


I did the ol' chop stick trick for a bit but there something even better.

A clean cigarette filter works better than wood, well for my set up anyways. If you place it just right, you will have a ton of small bubbles that gently drift in the water, much like dandelion's seeds on a warm summer's breeze.

Oh how they swirl and tango in a fine mixture of diffusion, only to disappear once the dance is done. Umm.... try it out.


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