# DIY CO2 for nano tanks



## lainealex (Sep 27, 2009)

I am trying to use DIY C02 in a ten gallon and in a five gallon tank. I have the units working, but I am unclear about how to prevent an overdose of C02 in such small tanks. How can I regulate the amount that is getting into the water? 

Also, what is the best way to stop the C02 at night - should I just unscrew the tops/pull out the diffusers?

Finally, what are my options if this DIY is the wrong approach for nanos? I don't want a huge canister situation since these tanks are in my living area and I can't build cabinets under them.

Thank you all,

Lainey


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## lainealex (Sep 27, 2009)

I forgot to add that the ten g is a plants-only tank, although it would be nice to add fish at some point. 

The five g houses plants and a single male betta, and that's all I plan to keep in there. Since the betta breathes surface air, maybe this affects my level of concern?


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## Darkblade48 (Jan 4, 2008)

Unfortunately, that is one of the disadvantages of using DIY CO2; there is really no way to directly regulate it. 

If you want an extra layer of security, you can put an air pump on a timer so that it comes on at night (you can leave your CO2 running 24/7 this way; that way, you won't forget to unscrew/screw the cap). This will prevent too much CO2 from accumulating at night.

For your 10g, you can leave the CO2 running 24/7 without any concerns, as there are no fish in it right now.

As for the 5g, you can do the above.


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## suethedino (Nov 8, 2009)

I used to have 2 DIY CO2 bottle for my 10 g, but it was almost impossible to overdose CO2 especially with DIY. I wouldn't worry about overdosing it as long as you follow the known recipe in the forum. I inserted my co2 tubing into a small powerhead under a timer, so it only diffused co2 mist during the day and stopped at night. (Once the powerhead stops, co2 bubbles stay inside powerhead or a big blob of bubble just goes straight up to the surface.) Eventually I didn't like the bulk of powerhead and it sprayed out too much mist so I took it out and switched to two glass diffusers for each bottle. I wasn't able to stop co2 at night, but my fish never showed any signs of gasping or stress and never had overdose issues.
But, after 6 months dealing with yeast bottles and sludge build-ups and fluctuation in co2 level, I decided to get a pressurized system and now I am much happier with the result. Everything is now so much easier and cleaner. After only a month, all of my algae is gone and I didn't have to make yeast bottle every 2 weeks, no need to clean diffusers every week, and I can precisely control co2 level. I also have a space issue, so I got a small 2.5 lbs tank. I think some people also go with ADA system or paintball system for a small space.


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## accordztech (Dec 6, 2004)

I OverDosed co2 in my 12 gallon with my DIY co2 (2 liter bottle 1/4 tsp yeast). Fish looked drunk, I thought they were dead until I poked one and he darted across the tank 

So I run an air stone at night and they have been fine ever since.

I say run full blast then at night when the lights are off run the air stone. I have a long air stone that I sit behind the plants, when its on its a nice bubble wall especially when the night lights kick on its really pretty hehe.


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## bigboij (Jul 24, 2009)

ive OD'd DIY C02 on my 20h a couple times, i have had plenty of dead shrimp and tetras to prove it. i use a airstone every night now.


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## lainealex (Sep 27, 2009)

Thanks for all these replies. I have a few questions:

1. Where is the PT DIY yeast recipe please?

2. Would the Red Sea Nano filter (which runs at the surface breaking the surface tension) be an alternative to the airstone? I think the airstone pump will drive me crazy with the vibrations and noise.

In my pressurized CO2 tanks I use the spray bars at night to break the surface, so was wondering if the RS nano filter would work for this?

3. Finally, does everyone else use spray bars to break the surface at night with pressurized systems? Maybe it's not necessary?

Thanks everyone -

Lainey


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## Darkblade48 (Jan 4, 2008)

lainealex said:


> 1. Where is the PT DIY yeast recipe please?


Most people use the following:

2 cups sugar
1/4-1/2 teaspoon yeast.
Fill a 2L pop bottle about 3/4 full

Be sure to activate the yeast in a small amount of sugar water first (i.e. whisk it with a fork). Then, pour it into the 2L container. Also make sure that the water is tepid (i.e. not hot).



lainealex said:


> 2. Would the Red Sea Nano filter (which runs at the surface breaking the surface tension) be an alternative to the airstone? I think the airstone pump will drive me crazy with the vibrations and noise.


As mentioned, an airstone would just be an additional insurance policy. Your HOB filter may provide enough surface agitation at night to prevent too much CO2 from accumulating. 




lainealex said:


> 3. Finally, does everyone else use spray bars to break the surface at night with pressurized systems? Maybe it's not necessary?


It more or less comes down to a game of fine balance; you don't want so much surface agitation during the day that all your CO2 is offgassed. However, you want enough surface agitation so that at night, too much CO2 does not accumulate.


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## bklyndrvr (May 24, 2008)

I OD'd DYI CO2 before. I had two 2L on a 10gallon. When I looked at the tank in the morning, I found one of my fish pale and swimming weirdly. I thought it was dead, but decided to put it into a cup. After having it in the cup for a little while with some fresh water from another tank, I noticed that the fish stabalized and got it's color back.


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## lainealex (Sep 27, 2009)

Is it possible to use a recipe with much less yeast and get lower output of CO2 for these nano tanks? IE could you do 2c sugar to 1/8t yeast and get lower output?


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## Darkblade48 (Jan 4, 2008)

You would likely get a slower initial start, and the mixture would likely last longer, but you would still eventually get an exponential increase in CO2 production due to the shape of the growth curve...


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## daijoubu (Dec 7, 2009)

I would recommend a smaller bottle and a proportionately smaller batch. 1l bottle and half the normal yeast recipe. I'm using that and it seems about right, my drop checker stays green for a few weeks.


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## devadair (Nov 24, 2009)

for a 10gal how long would half of the normal recipe (using 1L bottle) last? Would one of those little glass diffusers off ebay work fine?


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## Darkblade48 (Jan 4, 2008)

It may last up to a month at best, perhaps closer to 3 weeks. It is hard to say.

The glass diffuser may or may not work; some of them require quite a high pressure before they will start delivering bubbles.


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## qxz06090 (Jul 5, 2010)

Darkblade48 said:


> It more or less comes down to a game of fine balance; you don't want so much surface agitation during the day that all your CO2 is offgassed. However, you want enough surface agitation so that at night, too much CO2 does not accumulate.


So you mean aquarium have two filters one is for morning and another one for night? If I set up like this do I need turn off the first one when lights off?



Darkblade48 said:


> It more or less comes down to a game of fine balance; you don't want so much surface agitation during the day that all your CO2 is offgassed. However, you want enough surface agitation so that at night, too much CO2 does not accumulate.


So you mean aquarium have two filters one is for morning and another one for night? If I set up like this do I need turn off the first one when lights off?


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