# DIY CO2 on a 55-gallon tank - how much is too much?



## oldweasel (Jan 13, 2007)

Hell all, relatively new at this. I have a 55 gallon community tank setup with 2 140 GPH powerheads that I have rigged up to have two 3-liter DIY containers injecting CO2 into the sponge portion of the powerhead intake. I currently get a good "spray" of CO2 from each powerhead every 2-3 min.

I have ~20 small (1-2 in.) fish in the tank, and just have basic plants (java fern, scarlett, etc). 

My worry is that I am putting too much CO2 into the water and harming the fish, especially since the CO2 cannot be cut off at night (well, not without a big boom  ). 

Is this a safe setup for the fish? How can I tell if things are getting dicey in there? Should I run an airstone into the tank at night?

Really want to get into basic planting, but an afraid of killing my wonderful fish. 

Thanks in advance for the help!


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## Erlian (Aug 11, 2009)

*Sympathy *

I also have a 55g tank, and I haven't started on Co2. Perhaps we can help each other out? To the best of my knowledge, you can attach your powerheads to a timer that synchronizes with your lights. Simply plug the timer to the wall, plug lights+powerheads into the same socket, set whatever time you want, and when the lights go out, the Co2 keeps producing but stays in the bottles till' morning. Now here's your part of the deal-  what do you mix into the bottles and how well has the Co2 done? Thanks and you're welcome!


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## tuffgong (Apr 13, 2010)

IME DIY C02 can't produce anywhere near enough CO2 to harm your fish in a 55g. The tank is just too big. If you were able to get concentrations of CO2 high enough to harm fish from DIY in a 55, more people would be doing it as a long term solution. When the fish are in distress from lack of O2 you will see them near the surface gasping for air. If ur really worried u can run an airstone at night.


You would get better results from a gallon of Metricide 14 and it would be way less work.


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## Hoppy (Dec 24, 2005)

When I had CO2 going through a powerhead to chop it up into microbubbles, on a 40 or so gallon tank I had a big bubble about every 2 seconds. That didn't produce too much CO2 in the tank. This type of setup makes a perfect bubble counter because you can hear the bubble hit the powerhead rotor from clear across the room.


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## MlDukes (Nov 24, 2009)

If your worried about Co2 levels at night simply put the powerheads (diffusers) on a timer.


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## Airphotog (Aug 21, 2009)

I do not think you will have a problem with DIY CO2 in a 55 killing your fish..


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## mordalphus (Jun 23, 2010)

Why supplement CO2 in a tank full of low light plants? Are you planning on getting high tech soon? If so, a 55 gal will benefit very little from DIY CO2. I know that I have a 20 gallon long that requires 8-10 bubbles per second with 6 watts per gallon to keep the drop checker green. I could only imagine what a 55g would require.


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## Hoppy (Dec 24, 2005)

CO2 helps the plants even with low light and low light plants. It is always worthwhile. If you have a good level of CO2 in the water, you can grow high light plants in low light, but slower than in high light. Low light plants grow faster with CO2. With low light you don't need to push the amount of CO2 in the water so high that you have to worry about the fish, just enough to get a green drop checker, or even somewhat blue green will be fine.


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