# DIY CO2 Generator



## jsm11482

For any of you (flattrack) who are interested in building your own CO2 generator, here is how it is done. Very, very easy and super cheap!

You will need:
1x 2liter Soda Bottle, emptied
1cup Sugar
1tsp Yeast
1tsp Baking Powder
Fresh Warm Water (not from the aquarium)
CO2 Proof Tubing
Small amount of silicone sealant

1) Drink the soda, preferably in one sitting.
2) Drill a hole in the soda cap large enough so the tubing will fit snuggly.
3) Push the tubing through the soda cap so it sticks out maybe 1/2 inch through the bottom of the cap.
4) Seal around the tube on the top and bottom of the soda cap, allow it to dry and make sure that it is air tight!

Once the silicone is dry and it is air tight, it's time to create some CO2!

1) Add the sugar to the bottle (1 cup).
2) Add the yeast and baking powder (1 tsp each) on top of the sugar.
3) Add warm water (1 liter) to the bottle, leave the top 4-5 inches empty as this room is needed to produce the CO2.
4) Cap the bottle and put the other end of the tubing into the intake of your canister filter (in the tank).

The CO2 should start being produced in a day or so, you may notice the occasional bubble being released into the intake of your canister filter. The CO2 will get all mixed up inside the filter and will dissolve into the water. If you were to just place the tube in the tank and let it bubble, the CO2 would leave the tube and float right to the top of the aquarium and would be pointless.

As far as the measurements go, you can figure out what works best for you. The sugar is like food for the CO2 generation so the more sugar you use, the longer the mixture will last. The yeast is what actually reacts and creates the CO2 (along with the water and sugar of course). And the baking powder is used to help stabilize the CO2 production. The amounts stated above should last about 2 weeks.

One 2 liter should be good to supply CO2 to a tank up to about 50 gallons. For larger tanks, just build more CO2 generators!

By the way...

You can also just plug the tubing into an airstone and let it mix with the water that way (but the canister filter method will probably work better).

The CO2 may change the PH of your water.

Once you have started using CO2, don't stop as this will again change the PH of the water. Also, do not close or kink the tube as this will cause excessive pressure to build up in the CO2 canister and it may explode. Although it would look/sound cool, it would suck to have to clean it up.

Also make sure that you have good lighting as it is needed for your plants to grow!

Good luck!


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## Nick

THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU THANK YOU
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


That is very very very appreciated by me! I am going to start building it now! Thanks a lot again,

Nick
( Oh and I will show my steps in DIY )


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## jsm11482

Cool, I would have built one tonight, taken pics and posted them but I don't have a 2liter bottle and am too lazy to drive a mile to the grocery store :wink:


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## Lupin

No pics?:question:


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## jsm11482

Hi Blue - yes I already had one when I wrote this so no pics from me, Nick is going to build one and hopfully take pics, then we can hopefully merge the pics into the original post??


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## Lupin

jsm11482 said:


> Hi Blue - yes I already had one when I wrote this so no pics from me, Nick is going to build one and hopfully take pics, then we can hopefully merge the pics into the original post??


Sure.:thumbsup: No sense reading two separate threads when they are the same topics.:mrgreen:


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## dprUsh83

This may be a silly question, but why do you need to generate the CO2?


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## Nick

It's benefical for plant growth. Bottom Line.


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## dprUsh83

Oh okay cool, thanks!


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## The Dude

*oddly enough...*

I have used this trick before... but not in an aquarium.

The byproduct of the yeast eating your sugar is ethyl alcohol. I called it sugarwater wine and flavored it with kool-aide after it brewed. it's not terrible tasting, but honey tastes better.

so if you do use this method to make CO2 for your tank, you can drink it once its done bubbling


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## jsm11482

I'm gonna have to pass on that, it smells pretty nasty when I change it out!


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## Squinchy

Off topic: Like the Dude said you can drink it but it can make you sick, but if you distill it, it makes around 87-98% alcohol witch you can add water to it and make it around 38-45% and then you run it threw 2 carbon filter made from PVC pipes and you got perfectly safe to drink Vodka baby


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## wejlick1

*hey*

well distilling it can be dangerous if you dont know what your doin... it can create methynol gas wich can make you go blind.... or so ive heard


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## okiemavis

Hello, I thought I'd revive this, as I followed these directions (with a few modifications), and I took photos along the way.

*SAFETY WARNINGS
-Co2 will lower the pH of your water, especially in a tank with low kh (buffering capacity). Water parameters must be carefully monitored after adding co2
-DO NOT use a glass bottle. The gas can build up in the bottle, especially if there is a blockage in the tubing, causing an explosion. Plastic can expand and will be more tolerant of increased pressure. Also, if the bottle explodes, plastic will not become the dangerous shrapnel that glass will be.*

Drilled a hole in cap with my Dremel to fit the tubing:









Put anti-siphon valve in CO2 resistant tubing:









Put tubing through hole in cap about 1/2 inch:









Seal around hole and tubing in cap (I used a hot glue gun):









Here's the tubing all connected:









I decided to test out a co2 diffuser which I ordered on ebay for $2 (not including shipping), many diffusers will not work with DIY systems because it's not pressurized, but this one is advertised to work:









Add one cup sugar:









1 Teaspoon yeast:









1 Teaspoon baking powder:









Add warm (not hot) water:









Leave a few inches of space for the gas:









Add to tank!


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## tongg02

*co2 diffusion*

the end of my diy co2 generator tubing is under aboot four inches of sand, gravel, and lava rock. aboot twice a minute I get a burst of small bubbles. I will construct a diffuser next paycheck, am I getting any co2 diffusion with this setup?? I set this up 48 hours ago so I can't tell if my plants are responding yet


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## jsm11482

probably not, at least not much....


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## Trio123

Hello, I pretty much did this exact set-up (except with an airstone on the end) and I had one problem. The fluid from the soda bottle would sometimes evaporate up (dont ask me how) then drip down the line and into the tank. I didnt know if this was dangerous or not so I took it off the tank. Does this ever happen on your system? Also where did you get that diffuser? Has it worked so far?


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## jsm11482

No, it doesn't happen to me that I've noticed. You're probably adding too much water to begin with. Try with less ingredients! Good luck!


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## southafrica1001

hey can i use a 1 liter bottle as its only an 8 gallon tank? and if i can should i jkust half the recipe?


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## jsm11482

Yes, you can.


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## southafrica1001

thanks for your help


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## Tyyrlym

okiemavis said:


> Hello, I thought I'd revive this, as I followed these directions (with a few modifications), and I took photos along the way.
> 
> *SAFETY WARNINGS
> -Co2 will lower the pH of your water, especially in a tank with low kh (buffering capacity). Water parameters must be carefully monitored after adding co2
> -DO NOT use a glass bottle. The gas can build up in the bottle, especially if there is a blockage in the tubing, causing an explosion. Plastic can expand and will be more tolerant of increased pressure. Also, if the bottle explodes, plastic will not become the dangerous shrapnel that glass will be.*
> 
> I decided to test out a co2 diffuser which I ordered on ebay for $2 (not including shipping), many diffusers will not work with DIY systems because it's not pressurized, but this one is advertised to work:


How is that diffuser working? What kind of pH change did you see after adding the CO2 to the tank?


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## Kim

Could someone please explain to me how your fish don't get shocked during water changes when you are using CO2? It seems that if it lowers the pH of the tank water, then you do say a 25% water change with your tap water of a higher pH, then it would shock your fish. How much does the pH change? I have a canister filter on my 15 gal. so this would work great for me, but I don't want to play around with my pH too much or hurt my fish. Thanks.


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## jsm11482

Because it is "safely" changing the water parameters. It is not altering the hardness or PH in an unsafe manor. Maybe others can explain better?


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## Blaxicanlatino

so as long as the KH is good and with good water buffers then the pH change shouldnt change much. If the KH is insufficient then C02 shouldnt even be used until KH and water hardness is better


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## Blaxicanlatino

How often should you change the contents within the generator? When the bubbles finally stop appearing?


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## Blaxicanlatino

did that diffuser work okeivamis?


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