# DIY CO2 reactor



## Innocent159 (Jul 16, 2015)

Hey, I have a lightly planted fish tank but my lfs suggested I make a diy co2 system and a forum member suggested fertiliser for better growth. With my second try i got the reactors correct and the pressure is building in the 2 soda bottles.
I have 2 2liters with co2 mixture in and the pressure is building in the bottles but no bubbles in the tank.
I connected the bottles to a sponge filter , air house and air stone
My question is does it affect the pressure if i have 3 (diffusers) exit points? Will this cause it to fail? And should i change it or will there build enough pressure to force co2 out of all 3 points


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## corina savin (Jul 11, 2012)

If the three diffusers are not identical, I believe the gas (CO2) will escape through the one that has the least resistance.


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## Innocent159 (Jul 16, 2015)

That was what i was thinking and when i tested the 3 diffusers with my air pump. The sponge filter had the least resistance. I connected the sponge directly to the 2 bottles and another T valve for the other 2 exits.
So i should remove it and connect one diffuser?


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## corina savin (Jul 11, 2012)

Let's clarify few things:

1. The bottle with the yeast mixture is not a CO2 reactor (more on that if you wish).

2. If you are using the two bottle method, the second bottle should be filled with water only.

3. Out of the three "diffusers" you mentioned, the airstone is the only one I would use, providing you place it at the bottom of the tank and it creates very fine bubbles, like a mist that is floating in the tank water, not heading straight to the surface


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## Innocent159 (Jul 16, 2015)

I have two bottles with mixture and why should the second one be only water if you have a bubble counter (gas seperator)?
I already put the co2 on the air stone at the bottom of the tank and the house on the air pump (running it at night only)
Any more sugestion/help would be appreciated. Thank you very much.

And why isn't it co2 reactors (saw on google when i did the diy co2)


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## corina savin (Jul 11, 2012)

The second bottle is like a storage. CO2 coming from the yeast/sugar mix is "washed" by bubbling it into the second bottle's water. This way, the second bottle also serve as a safety way to prevent syphoning yeast mixture into the tank. You will notice a mucus-like growth on the airsone if you don't use water bottle. No big deal, however, it clogs the finest pores on airstone.
As for CO2 reactor, that is the most efficient diffusion method. Gas (CO2) and tank water are mixed together untill all CO2 is disolved. Ideally, that is happening outside the tank, in the reactor chamber. Using a CO2 reactor it's not only economical (since no CO2 is lost into the air) but also esthetical, because the water in the tank is crystal clear, free of bubbles.


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## Innocent159 (Jul 16, 2015)

Thank you. Currently i have two mixture bottles (half full to prevent foam going in tube). I will add another one liter with half water to prevent cloging. Will this be beneficial and would you suggest buying co2 reactor?


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## corina savin (Jul 11, 2012)

A reactor sounds like a good idea if you can adjust the CO2 flow to match the amount of gas your reactor can dissolve in a given time. You don't want to overwhelm the reactor (and have CO2 gas sitting there, waiting to be disolved) or restrict the CO2 flow from the bottle and risk an explosion.
Ideally, CO2 reactor works with a regulator on solenoid and a quality needle valve that can fine tune CO2 to 1 bubble per second or less.


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## Innocent159 (Jul 16, 2015)

Ok but one laat thing. With the air stone sometimes i get big bubbles that rise fast, would you suggest a powerhead instead or is there any other way i can solve this problem?


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## corina savin (Jul 11, 2012)

I would replace the airstone with a Fluval ceramic disc diffuser. It requires a bit of pressure to work but it produces fine bubbles. A powerhead aimed at the disc will help spread the mist around and keep the bubbles in the water longer, for a better solubility. Personally, I did not like the powerhead; floating plants were blown to one side and the fish were not happy. You can try the output of a canister filter instead....


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## Innocent159 (Jul 16, 2015)

My guppies already dont like the. Filter when its ona full but i would look at the disc diffuser. I was also contemplating a long rectangular shape difusser for lengthier spread of bubbles


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## Innocent159 (Jul 16, 2015)

How can i get more pressure from the 2 bottles. Co2 only coming out of one pore on the air stone?


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## corina savin (Jul 11, 2012)

Most CO2 is produced in the first few days. The yeast is slowly dying because of the alcohol/vinegar byproduct.
If everything is right (fresh yeast, proper mixture, well sealed system, good diffuser that is not wasting CO2), you might get it going for about two weeks. During this time, the bottles should feel hard to squeeze , just like a full pop bottle.
I would start a new mixture after you get a proper diffuser.


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## Innocent159 (Jul 16, 2015)

My new diffuser. Didnt get the circular diffuser but this one is better than what I had. Only problem is that i dont get enough bubbles at once hense i want to increase pressure


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