# DIY CO2 - Why 2 liter bottles?



## Rowerzysta (Jul 29, 2008)

Soda bottles are designed to handle some pressure. Milk jugs might be air tight, but have you ever seen a jug of milk pressurized? Its just not what it was designed to do.

Now, having said that, any plastic or maybe even glass container will work for making co2...but the point is to go about it the safest way possible. If for example you would get a clog somewhere, and pressure would start to build up in your container, it is believed that a soda bottle would handle the pressure build up the best. The question is how much do you want to risk your sugar and yeast mixture splattered all over your cabinet.

Another point i can think of is that soda bottles are meant to hold some liquids and CO2, exactly what you will be making. So you can have some confidence that the CO2 will not react with the plastic of the soda bottle or the cap in any way.

Lastly...about the recipe, if you double the size of the bottle, double the rest of the ingredients as well. Just remember that a bigger bottle will give you more co2 but it will not make it last longer.


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## airborne_r6 (May 2, 2008)

You will pop the top off of milk jugs. Soda bottles are designed to withstand the pressure as previously mentioned. Gatorade bottles have also been used and I used a 1 gallon apple juice bottle.


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## james0816 (Jun 26, 2008)

x2 on the Gatorade bottles. I swapped out all my 2L bottles in favor of the OceanSpray bottles and using small Gatorade bottles as my seperator. They seal a lot tighter and are less prone to leak through the threads.


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## Twimbo (Oct 10, 2009)

james0816 said:


> using small Gatorade bottles as my seperator.


What is a seperator?


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## jreich (Feb 11, 2009)

i also use 2 1gal ocean spray bottles because the strong and have handles.


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## Twimbo (Oct 10, 2009)

Twimbo said:


> What is a seperator?


I will answer my own question. I found a great thread in this forum that explains what a separator is, in a DIY CO2 system. Basically, its a chamber with air (or CO2), between the CO2 reactor and the tank, designed to catch any yeast that might get into the tubing, before it reaches the tank. These separators, can also be used as bubble counters. 

See this thread for more info.


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## james0816 (Jun 26, 2008)

Twimbo said:


> I will answer my own question. I found a great thread in this forum that explains what a separator is, in a DIY CO2 system. Basically, its a chamber with air (or CO2), between the CO2 reactor and the tank, designed to catch any yeast that might get into the tubing, before it reaches the tank. These separators, can also be used as bubble counters.
> 
> See this thread for more info.


Yeppers...not required...but HIGHLY recommended.


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## Mowze (May 11, 2009)

I use a 5L mineral water bottle


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## Hurriken (Mar 11, 2007)

I use two 2L bottles with a splitter and two of _those thingies that keep the water from backing up_ (I forgot the name) I heard once of tops blowing off of Gatorade bottles and water bottles. Actually one of my bottles is a Hagen Plant gro. I wish I could find a used one cheap somewhere. 

Anyway, I use two bottles an alternate replenishing them every other week to keep the flow more stable. 

What tubing connectors do you people use in the soda bottles?


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## cole99v (Oct 13, 2009)

2 liter bottles I think are just easy to find, I use a 3L for my 39gal. I tried to use containers like milk jugs and orange juice bottles but I noticed any jug with one of those soft plastic short caps will leak easily and/or blow the top off. 

As for connecting i just popped a hole in the top and siliconed the tubing into it then into the separator and use a plastic flow valve after that just incase.


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## sollie7 (Jul 19, 2009)

i use a water bottle


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## halfsour (Nov 19, 2009)

anyone got pics?


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## bcdudley (Nov 18, 2009)

I have been using a 3l soda bottle that is 3 months old and not even half way empty yet. Still going strong at a good 1 bubble every 3-5 seconds.

I mix 4 boxes of Jello with 4 cups of sugar (cooked as per the directions on the box of jello). Pour them in and let it congeal overnight in the fridge. I then mix 1 teaspoon of yeast with 1 cup of warm water and a pinch of baking soda (I think it is baking soda) and pour that on top of the jello mix. I then seal it up tight with silicone or rtv. It produces good pressure after about 2 hours and will last at least 4-6 months.


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## Twimbo (Oct 10, 2009)

*Jello*

I just found this thread, which goes into more detail on the Jello method.

http://www.plantedtank.net/forums/diy/9916-jello-co2-thread.html#post85288


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## bcdudley (Nov 18, 2009)

Wow, I guess I have just been really lucky with my batches. I have never had any of the problems described by people in that thread. The first one I ever did was a 2l bottle that lasted about 3 1/2 months. Since then, I have done two more 3l bottles and am on my 3rd one now. Each of those lasted at least 6 months with 0 maintenance. The one I have now is 3 months old and still going very strong. I do not have any issues with foam as the liquid is a good 4-6 inches from the top of the bottle. I have a 3" length of hose coming out of the bottle that uses a hard tube as a splice for quick changes. It creates enough pressure to run one of those ceramic disc diffusers.

I plan on building a dual bottle setup once I get my 29gallon tank up and going. I will be using a Rex Grigg style reactor for that tank.


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## MoonFish (Feb 12, 2006)

I used a 1 gal plastic gas can.


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## Whiskeyfox (Oct 16, 2009)

Here's mine before i added a second bottle to the left with a T, and a second check valve on the co2 line up:










It's a waterbottle from Wal-Mart, sells for $2.00. It's 2.2L, has a handle and a wide mouth, and the inside of the sippy stopper drilled out tightly fits a hose without having to use sealant. Also, I added plumbers tape to the threads. The gas exchange jar is a 250ml Purigen plastic jar from Seachem.


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## ermano (Nov 15, 2009)

I'm currently trying the jello version. It's producing bubbles...we'll just have to see if it'll stay consistent.


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## sdy284 (Feb 21, 2008)

bcdudley said:


> I have been using a 3l soda bottle that is 3 months old and not even half way empty yet. Still going strong at a good 1 bubble every 3-5 seconds.
> 
> I mix 4 boxes of Jello with 4 cups of sugar (cooked as per the directions on the box of jello). Pour them in and let it congeal overnight in the fridge. I then mix 1 teaspoon of yeast with 1 cup of warm water and a pinch of baking soda (I think it is baking soda) and pour that on top of the jello mix. I then seal it up tight with silicone or rtv. It produces good pressure after about 2 hours and will last at least 4-6 months.


hmmm... 4-6 months eh? Thats the kind of low maintenance method i'm looking for. I don't want to be changing out bottles every other week. 

What method do you use for defusing? Bubble counter?


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## Twimbo (Oct 10, 2009)

ermano said:


> I'm currently trying the jello version. It's producing bubbles...we'll just have to see if it'll stay consistent.


Ermano - how is your jello experiment going?


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## anastasisariel (Oct 4, 2009)

I really like Whiskey's deal.


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## ermano (Nov 15, 2009)

It is going exceptionally well...It's been, what...2 and a half weeks? and I'm still getting about the same amount of bubbles as I started. It works very well actually, I'm very impressed. You can actually see the jello go down as time goes on...It's gone down maybe .75" in the past 2 weeks.


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## Franzi (Dec 7, 2009)

I use one of those big wine jugs with a rubber stopper and airlock. One airlock is connected to a hose and connected to the bubble ladder, the second is a regular 'ol airlock I put on the bottle at night when the lights turn off. That's my poor man's way of controlling DIY CO2.


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## Twimbo (Oct 10, 2009)

ermano said:


> It is going exceptionally well...It's been, what...2 and a half weeks? and I'm still getting about the same amount of bubbles as I started. It works very well actually, I'm very impressed. You can actually see the jello go down as time goes on...It's gone down maybe .75" in the past 2 weeks.


How many bubbles per second - or how many seconds per bubble??

Is this for the 3.5g tank?


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## bcdudley (Nov 18, 2009)

I have been using this one, but I would recommend a ladder or something else. The diffuser makes a loud chirping noise and gets annoying going all day.

I am waiting on a drop checker to come in so I do not know how well it is working. When it comes in, I will post my results.


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