# 2L DIY CO2 Reactor



## carpio77b (Feb 28, 2008)

I have a 29g heavily planted tank (crypts, vals, java fern, java moss, some floating lily, anacharis) with a 2x24 t5ho light fixture. Running the lights 13 hr.s a day. I have only minute amounts of algae growing on the crypts. I fertilize once every two weeks.

I recently added a CO2 generator via the 2 liter pepsi bottle (1/4 tsp live yeast, 1 cup cane sugar, 2 cups water) CO2 production is decent - I can see that the bottle is carbonated and bubbling into the water.

My question is, how to recharge the slurry. Should I add more yeast or dump the whole thing and start with all new ingredients? Also, how often should you change the mixture?

Thanks in advance for your responses.


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## kornphlake (Feb 12, 2004)

Dump the mix and start over when the bubbling slows down, I've been using 1 cup sugar and 1 tsp yeast in about a quart of water. I get lots of bubbles the first day (1 every 2-3 seconds,) by the end of a week I'm down to one bubble every 5-6 seconds after 10 days I get almost no bubbles. I keep two bottles going and try to rotate them every 3-5 days so that I have a steady rate. I know a lot of people have sucess using 2 cups of sugar to 1/2 teaspoon yeast, for whatever reason I didn't get very much CO2 that way, maybe 1 bubble every 10 seconds, but it would stay pretty steady for 2+ weeks. I started getting a lot of algae so I tinkered with the mix until I could get more bubbles.

You can keep the yeast and just add more sugar, you have to dump the water though because the alcohol produced eventually becomes toxic to the yeast. If you want to keep your yeast simply pour off the liquid allowing the film of yeast that sticks to the bottle to remain, add water and sugar and you're back in business. I was doing this but after a month or so the yeast quit producing so I started over, it seems like I get more consistant bubbles if I replace the yeast every week.


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## Rick_Lindsey (Aug 26, 2002)

carpio77b said:


> I have a 29g heavily planted tank (crypts, vals, java fern, java moss, some floating lily, anacharis) with a 2x24 t5ho light fixture. Running the lights 13 hr.s a day. I have only minute amounts of algae growing on the crypts. I fertilize once every two weeks.
> 
> I recently added a CO2 generator via the 2 liter pepsi bottle (1/4 tsp live yeast, 1 cup cane sugar, 2 cups water) CO2 production is decent - I can see that the bottle is carbonated and bubbling into the water.
> 
> ...


Sounds lovely! Do we get pictures? .

Also, are you using a bubble counter?

-Rick (the armchair aquarist)


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## carpio77b (Feb 28, 2008)

Thanks for the recipe tips.

Do you think that an air wand would be a good diffuser? I've heard of people using air stones as diffusers but I would rather use my wand and bury it under the gravel. 
I'm getting over a case of ich right now :x and will be going on vacation for 8 days so I have alot of work to do before I leave (50% water change, clean filter, new yeast slurry, etc.) As soon as I get back, I will post a pic. Tank has been up for about 2 mo.s.


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## carpio77b (Feb 28, 2008)

Thanks for the recipe tips.

Do you think that an air wand would be a good diffuser? I've heard of people using air stones as diffusers but I would rather use my wand and bury it under the gravel. 
I'm getting over a case of ich right now :x and will be going on vacation for 8 days so I have alot of work to do before I leave (50% water change, clean filter, new yeast slurry, etc.) As soon as I get back, I will post a pic. Tank has been up for about 2 mo.s.


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## kornphlake (Feb 12, 2004)

A bubble wand would work a little, really you want to slow the bubbles down as they make their way to the surface so they have as much contact with the water as possible. I've got my tank setup so that the CO2 bubbles into the intake of my HOB filter, the bubbles get chopped into hundreds of tiny bubbles by the impeller then forced into the media. It seems to work okay, people with canister filters do the same thing but complain that occsionally air will accumulate in the filter and make it noisy or worse it will stop circulating water.

I've heard of people using limewood diffusers with good success, they produce a fine mist of bubbles, much finer than a bubble wand.


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## aussieafricans (Dec 19, 2007)

what about pluging it into the air inlet of a powerhead where the output is then it would get dispersed around the tank.


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## kornphlake (Feb 12, 2004)

There are several popular methods of diffusing CO2, pretty much anything with an impeller will work, the goal would be to break up the bubbles into smaller bubbles and put them in the way of some current. Some people modify the impeller of a power head by drilling several small holes in the blades so that it will smash the bubble into even smaller bubbles, I believe the term used is needle wheel, if you want to do a google search on that. A Reactor like this: http://www.plantedtank.net/articles/DIY-CO2-Reactor/2/ is probably the best way to dissolve 100% of the CO2 but doesn't work for everyone, I don't have enough room in my 10G tank for something like that. Other methods are diffusers like these: http://www.drsfostersmith.com/Product/P ... =3578+3747 although it's been reported that these clog easily and are usually more suited to a pressurized CO2 setup instead of a low pressure DIY, honestly I'd try a limewood airstone for $2 before spending $20 on a glass diffuser, and I don't think I'd buy the $20 diffuser from F&S, it gets poor reviews, the ADA diffusers get good reveiws but cost close to $100.


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