# CO2 question



## Mariah (Feb 8, 2006)

what exactly are "CO2 injections" and how do you do it?


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## Guest (Aug 4, 2007)

CO2 is Carbon Dioxide. Plants take this in and use it during photosynthesis (remember this from biology classes) and they release oxygen. Plants need carbon dioxide to grow. In low light tanks, you don't have to add carbon dioxide because there is going to be a little in the water. In higher light tanks though, the plants grow faster due to more light, and the carbon dioxide in the water isn't enough, so you must "inject" CO2.

To do this, on smaller tanks the yeast method will work fine. You put sugar, water, and some baking yeast into a 2 liter bottle. Drill or poke a hole in the top and feed some airline through the top, put an inline check valve, then more airline that ends at a diffusor or reactor to get the co2 into the tank. The yeast feeds off of the sugar and produces carbon dioxide.
http://www.plantedtank.net/articles/DIY-Yeast-CO2/7/

Another way to do it (the easier, but more expensive way) is to buy a carbon dioxide tank and use it to inject the co2.


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## Mariah (Feb 8, 2006)

hmm.... couldnt you just use a bubble strip or take a straw and blow in it for a couple minutes a few times a day?

i knew what co2 was btw. haha. i just didnt know how the injections worked or if there was more to it than the co2 itself.

i would like to know if i have a high or low light tank. i have 10-gal aquarium with 2 twenty-five watt bulbs. doesnt that average out to 5wpg? and wouldnt that be fairly high?


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## Zoe (Feb 26, 2006)

> hmm.... couldnt you just use a bubble strip or take a straw and blow in it for a couple minutes a few times a day?


A bubble strip, if you DID get CO2 into it (air pumps just put air in the tank and actually remove CO2 from the water), would produce bubbles that are just too big to disolve in the water. Basically, the bubbles of CO2 have to disolve and disapear before they hit the surface (either by being really tiny bubbles, or by going through a maze so they have a long way to go in water before they can go to the surface).
Blowing into the tank would not work. First of all, the bubbles would again burst at the top. And second, your breath does not produce enough CO2 that a few minutes of it into the tank would have any effect at all. You need to steadily input bubbles during all of the daytime (1-3 bubbles per second, depending on the tank size and other parameters).

5 WPG is pretty high, yeah. You could grow a variety of plants with that lighting.


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## Mariah (Feb 8, 2006)

ok. so could you get a co2 tank at a regular pet/aquarium store? and about how much do they cost?


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## Damon (Jan 18, 2005)

Some stores yes but most no. Tanks are acquired on-line or locally at welding shops, fire supression stores and other locations. It IS illegal to ship a full co2 canister so any you buy on-line will be empty. Prices vary from $40.00 to $200 depending on size and location. Regulators/solenoids/needle valves are most practically bought on-line for $75.00 to $140.00. Then there is diffusion method...........


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## Zoe (Feb 26, 2006)

Most stores will sell the equipment you need such as regulators, solenoids and needle valves. They come in a combo pack that is like 60-100$, and is of fair quality. You can also find various diffuser (that get the bubbles to disolve into the water), 5-50$. 
The tank you will probably have to buy separately online or from a local supplier, they're pretty cheap for the smaller ones (3-10lbs), and it costs 10-30$ to fill it up with CO2.


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## Mariah (Feb 8, 2006)

wow. that's over wat i'd like to pay. the plants were only $2 apiece, so i'll just see how they do without it. one of them seems to be doing ok, but the other one... idk i'll just have to see.

but you know, i at least wanted to get some sand and fertilizer for them, and i looked at 2 different pet stores that sell aquatic plants and neither had the fertilizer or even sand. where could i buy those?


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## Damon (Jan 18, 2005)

What kind of sand do you want?


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## Mariah (Feb 8, 2006)

any kind that might help my plants live a little longer theyre dying quickly possibly from living in the rocks


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