# CO2 and Oxygen



## CatB (Jan 29, 2012)

i don't know about an airstone, but i run DIY CO2 with an azoo "oxygen plus" sponge filter in the tank, serving as the main form of CO2 dispersal (i have the airstone from the CO2 jammed right up against the sponge filter so it gets sucked in), and my plants are still showing the effects of the CO2. i don't think it's a problem, or not a big one.


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## brooklynfishman (Feb 12, 2012)

I am basically asking about the dissolved CO2 versus the dissolved O2 content in the water, if that makes sense.


I remember somewhere that Tom Barr said as well as others that having a high concentration of O2 in the water wont hurt the plants or CO2 content but will help the fish and dispersal of the CO2.

Did I get this wrong?

Does this mean that I feasibly can pump more CO2 into the tank with higher O2 levels?


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## pejerrey (Dec 5, 2011)

Beer has co2 from yeast for its bubbles, what happens if you throw an airstone in a pitcher? Your beer gets flat. This will cause ph swings that could be a problem for certain livestock or breeding, but it supposedly doesn't affect plants.

Surface agitation without splashing would do well too.


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## senoufo (Nov 14, 2008)

C02 and 02 don't compete in terms of saturation.

c02 is a fuel for plants to help in photosynthesis ( which includes lights, nutrients...) and they create 02 by respiration as a by-product. Once lights out and c02 stopped they uptake 02 and give off co2.

you can have both at saturation point, so for 02 this is where your plants start to pearl, and C02 where your fish start to gasp and die.

if you want to disperse c02 you must have a surface agitation, pumping air in the aquarium in and by itself does not disperse co2( nor does it add 02 as 02 is not very soluble ), the surface agitation does as it breaks the boundary between air/water.

some people feel the need to run an airpump at lights-out to achieve a c02 dispersal, in three years of injecting c02 during lights-on i've never run an air pump at night, with minimum ph swing. 

your mileage will vary depending on how dense your planting is, livestock...etc.


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## pejerrey (Dec 5, 2011)

Sorry I didnt answer your questions:



brooklynfishman said:


> What is the consensus here...
> 
> Do you use an air pump at all? *Only with my first aquarium for like 6 months, after I learned that not the bubbles but surface agitation oxygenated the water, I used the filter outlet to do this and I never used an airpump again, silence is precious to me (but I think today you can find very silent pumps, better than back in the day)*
> 
> ...


 You can add extra oxygen by pointing powerhead to the surface brom a few inches below, if you are doing this use a sponge filter in the powerhead inlet. IMO airstones and all those bubbles are going to take the co2 out of your water as in the beer example I gave you above.

If you use an airstone I would think that you need to add more CO2 to reach desired ppm.

I add some CO2 24/7 from one regulator and I have another that injects more when the lights are on, this is as an experiment. I add *A LOT *of CO2 overall, and dont have an airpump nor livestock deaths/health issues. I do have a powerhead and the filter jet agitating the surface a lot, but *NO SPLASHING.*

BTW, dont add CO2 guiding yourself by BPM, that is not an accurate at all. Crank it up until you see that your lifestock doesnt like it, and then go down a notch. That said, never adjust CO2 and then go away, you need to be there to watch and monitor your PH.


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## they call me bruce (Feb 13, 2011)

co2 should pump when the lights are on --if you dont have surface agitation which you shouldnt if you want the co2 to stay in your tank for max growth; then 1 hour before your lights go out start your bubbler and let it run all night to 1 hour before the lights come on
you have to get rid of it at night your plants wont use it with the lights off.
If you use yeast u cant turn it off so you really need a air stone


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