# Bottle size & recipe of c02 for 5 gallon hex



## PlantsAndMe (Apr 3, 2005)

I have a 5 gallon hex and I want to make a DIY C02. My questions are simple:

1) How big should the two bottles be? (2nd diagram from Over Tolerance Pressure Release and Prevention Systems at http://www.qsl.net/w2wdx/aquaria/diyco2.html)

2) What the ideal recipe (amount of yeast, sugar, water, etc)

3) Can I use brass barbs?


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## Paul Higashikawa (Mar 18, 2004)

Whoa! I'm surprised to find that page still exists! Nevertheless, I am glad for it's a nice beginner read on CO2 injection. 

In my opinion, a 2-liter coke bottle would be just fine. Other similar bottles will do just as nicely. You want to leave a 2-3 inch gap between the top and the content level so as to build up a nice pressure of CO2. Other than that, there are a number of recipes out there. I have been using the 'Nyberg Method' with fairly good results(wondering what happened to the sticky I wrote on it?!) But here is a small summary of it:

-1 cup of sugar in a 2-L bottle
-1tsp of baking soda+1-2tsp of soy powder(or any other protein powder; soy being a really cheap kind, which is good for my budget)
-1tbsp of molasses
-1/4 or less of yeast(bread or wine)
-lukewarm water or can use water from fish tank

I found out it is helpful to mix the contents before capping as this will help initiate the pressure build-up. I often get faster CO2 start-up in this way; within one hour. As for the logistics, I will leave that to other people or you can easily find out why Prof.Nyberg does what she does in her formula by searching Google. Hope this helped.


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