# CO2 DIffuser



## 83mulligan (Dec 28, 2004)

I'm new to this and have done alot of reading lately on CO2 injection. I have been wondering why I never see any posts about using a ballast tank setup to diffuse CO2. It would seem to me that the best way to completely dissolve CO2 into water would be to set up an airtight ballast tank whereby CO2 is injected into the top of the ballast tank and water from the aquarium is pumped into the tank at the top and pulled out the bottom at a verly low flow rate and returned back to the bottom of the aquarium. 

I don't know how much contact time CO2 needs with H20 to completely dissolve, but it seems this could also be accomplished by simply creating a holding coil, injecting the CO2 at the beginning of the coil and pumping aquarium water through it at a low flow rate and returning it to the tank.

I also have some questions about lighting and tank setup. Please see my thread in the "new to planted tanks" forum to help me out.

Thank you,


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## 83mulligan (Dec 28, 2004)

*To take this a step further*

Could you not also have a 1 gallon holding tank with distilled water and a custom mixed macro and micro fertilizer package that you coud inject into the diffused CO2 stream at regulary timed intervals? The company I work for does stuff like this all the tme for the food/beverage industry on a larger scale so, I have access to the engineering minds that can make this happen.


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## gpodio (Feb 4, 2004)

Sounds similar to the upside down bell method. But surface area is key, meaning the more surface area of gas is in contact with the water the more CO2 will be dissolved. With this in mind, a fast flowing powered reactor would likely be the better choice. Otherwise feeding CO2 directly into a canister filter where it gets trapped in the filter media until dissolved or eventually burped out, both of these methods have been the most effective in my experience. I guess the canister filter method is similar to one of the methods you are describing, water flow is slower than in a reactor and gas is simply trapped until dissolved. I think most people today simply want their reactors/diffusers out of sight, for that an exterior reaction chamber placed inline with your canister filter or feeding directly into the filter itself is likely the most effective choice.

Giancarlo Podio


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