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Thursday, September 21, 2006

DIY CO2 Recipe: Duration vs. Intensity



The second most difficult part about adding a yeast-powered CO2 system to your planted aquarium, after ripping all your hair out trying to find where its leaking (see our article on building your own CO2 generator for step by step instructions on how to avoid this), is to find a recipe that fits your CO2 needs. You can find all kinds of recipes and resources online that tell you to boil containers, add baking soda, use honey, brown sugar, and all sorts of other crazy things. Take it from me: I've tried these and I still keep coming back to a basic recipe and procedure. The main thing to remember is that depending on what proportion you add the ingredients, you will either get very intense CO2 production for a short period of time, or milder CO2 production for a longer period of time. If you add more sugar and yeast, the CO2 production will be more intense, while adding less of both means it will last longer. This is because as yeast create CO2, they produce alcohol which eventually poisons the yeast and kills it. A smaller amount of sugar and yeast means the whole process is slowed down and lasts much longer. I opt for this type of mix, only because I find it a pain to replace the mixes every week, let alone every few days! My recipe usually produces CO2 at a fairly regular rate for about 14 days. It will continue to produce CO2 for at least another week or so, but it will produce less and less each day. This recipe works well in containers of roughly 2 liters (soda bottles, juice containers):

Ingredients:
2 cups sugar

1 tsp baking soda

1/2 tsp yeast (regular dry baker's yeast is fine, see picture)


  • Start with a small cup or bowl and add a small amount of lukewarm water and a pinch or two of sugar. Mix in the yeast with a fork, stirring vigorously until the water is bubbly. This will help to "activate" dry yeast by adding oxygen, preventing mass die-offs that occur if you just dump the yeast into the water. Let this sit while you prepare the container, or for at least 10 minutes, and stir every few minutes to keep the water oxygenated.
  • Rinse out your container if you have used it before to remove all traces of alcohol. Fill it about 2/3 of the way with lukewarm water. Tap water is fine.
  • Using a funnel, add the 2 cups sugar and the baking soda to the water in the container. If you've used the container before, it's likely you don't have a lid you can use to close it up and shake it, so just put the palm of your hand over the opening and turn it upside down over the sink and shake it gently, making sure to keep the seal with your hand. The point is just to dissolve most of the sugar in the water (otherwise it will just sit on the bottom). If you haven't used the container yet, wait to drill a hole in the lid till after you've shaken it up, just to save yourself a sticky hand.
  • If it's been about 10 minutes or longer, pour the yeast and water mixture into the container using a funnel. No need to mix it up, just put the lid on and it should start producing CO2 in anywhere from a few hours (I've had it start in around 1 hour!) to 12 hours depending on how well you activated the yeast.
If you don't have any bubbles after 12 hours, you've probably either got bad yeast or leaks. A leak is much more likely in a DIY setup like this and trust me, it will make you reconsider plunking down $300 for a pressurized CO2 system.

37 comments:

  1. What is the baking soda for?

    I agree, the simpler the better as long as it works.

    I use the same amount of sugar and yeast that you use. I also run 2 bottles alternating the refill once a week. Come refil time I rinse the bottle out with hot water untill it doesn't smell any more and refil it.

    I keep my sugar in one of those refridgerator pitchers with the little plastic lid on top of the screw on cap. I just flip the lid open and poor the sugar into the bottle. Add the yeast, shake well. Add the water - make sure it isn't too hot! Cover with my hand, shake well and screw the cap with the tubing back on at the aquarium.

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  2. Baking soda is made of Sodium Bicarbonate. It act as a catalyst to expedite the whole process of generating your CO2 bubbles. In another word, if you add baking soda, you will use a much shorter period to create your CO2.

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  3. how do i shut off the co2 at night. i know it is not absorbed at night, therefore raising the ph. how do i combat this issue

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    Replies
    1. Your best bet is to get a valve and either turn down the amount released or, if you've got a mild enough mix, turn it off. I leave mine running 24/7 without any issues, but I have a better than necessary aeration system and I use relatively mild mixes.

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    2. CO2 Lowers the PH , NOT RAISES IT

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  4. It is DIY ... I do not think you can shut it off.

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  5. "It is DIY ... I do not think you can shut it off."

    No, of course you can shut it off.
    All you need is an electronic valve that will stear your CO2 to different tubing that is connected with the open air outside (to avoid pressure buildup in the CO2 tank). Btw, shutting off DIY CO2 during the night is often worse than not shutting it off

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  6. iv setup my co2 DIY generator and so far its very promising.
    now its about 1 hour and i can see small bubbles.
    thanx DJKronik57

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  7. Using this recipe, how much should I use for a 1 liter bottle?

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  8. You do not have to turn off the CO2 just put an airstone and pump near it timed to turn on at night. I would also suggest before the CO2 makes it to the tank running it through another bottle filled with saltwater with 2 holes drilled in it one with an airstone the other for an outlet this will kill the slime that can clog your system.

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  9. One thing you can do to increase the amount of CO2 that gets dissolved into the water is to attach a nyquil cap, or something similar to the tube right above the airstone ( under water). This will trap the CO2 bubbles... allowing for more CO2 to be dissoved in the water.

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  10. I just want to say that this recipe is great. Using this recipe, and using a 64 oz V8 bottle, I've got about a 3 week average life span for CO2 production. Thanks for your great advice!

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  11. My diy co2 setup only produces co2 into my diffuser when I shake the bottle. then is see bubbles in the diffuser like crazy which last a while, but if i don't shake the bottle, no more bubbles, or only very infrequently. is there a problem with the pressure? i did 1 tsp yeast, 2 cups sugar, no baking soda. i'm on the 4th day...

    also i have a second bottle i use in between the c02 generator and the diffuser, with a check valve between 1st and 2nd bottle. 2nd bottle is empty but i see after 4 days about an inch of water has built up on the bottom. thanks!

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  12. hi followed all steps and its not bubbling after 13 hours now i remember reading somewhere that it wont work if your water is higher then 7.8 on the ph scale and mine is 8.3 would this be the problem?

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  13. what i've been using is a mixture of:
    2 cups sugar
    1 packet yeast
    1 Teaspoon baking soda

    use luke warm water I beat yeast with wisk for about 5 minutes..add half bottle of little bit warmer than luke warm water add sugar and baking soda..shake till dissolved..add yeast and do not mix together..gas using this method will start within 20 mins. I've been running my last mixture now going on 4 weeks..using a diffuser...

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  14. i followed your recipe/technique and bubbles are slowly but steadily streaming out. good stuff

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  15. FANTASTIC RECIPE! STILL PUMPING OUT LOTS OF CO2 9 DAYS STRONG. IT HAS BEEN STEADY TOO. THANKS!

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  16. A LITTLE TIP...IF YOU HAVE A CANNISTER FILTER, DRILL A TINY HOLE IN YOUR INTAKE SIDE SOMEWHERE ON THE TUBE. IT WILL GET ABSORBED INTO YOUR FILTER AND COMPLETELY DISSOLVE IN THE FILTER. YOU WONT SEE ANY BUBBLES COME BACK OUT INTO THE WATER. WORKS GREAT. MY PLANTS ARE BLOWING UP RIGHT NOW. IT'S ONLY BEEN A WEEK! MAKE SURE YOU DO IT BELOW WATER LEVEL, SO YOU CAN SEE YOUR BUBBLES GOING UP THE LINE. AFTER SETTLING DOWN, IT SHOULD MAKE A BUBBLE ONCE EVERY SECOND OR SO. JW

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  17. apart from a cannister filter how can i diffuse the bubbles?

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    Replies
    1. A short piece of BAMBOO CHOPSTIK, is absolutely great, [tiny bubbles. cut bamboo about 10mm long, trim end with razor blade, to make it smooth, stuff it into end of CO2 line , and place it in yr tank,
      Is the best fine bubble attachment I have ever seen,
      CHEERS

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  18. Check out http://www.aquatic-eden.com/2006/10/methods-of-diffusing-co2-in-aquarium.html for ways to diffuse the CO2 you generate efficiently.

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  19. Hi folks,

    Maybe a little late.. Here's how to build an effective DIY diffusor


    1. Take an undergravel tube /two depending on height of aquarium
    2. Attach covering vents to both sides (the top from where the air line goes in )
    On one side, fix the airline / output from 3. the DIY reactor
    on the other, widen the hole to accomodate a powerhead output pipe
    4. Fill the tube with Bio Balls

    Connect to powerhead/power filter and enjoy !

    You will need to ensure that the DIY has an aircheck valve to prevent water siphoning into the DIY output.

    You may also need to experiment a bit to ensure that the bubbles produced are completely dissolved.

    Run an airstone at night to prevent acute buildup.

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  20. DO NOT INSTALL ON THE "INPUT" LINE OF A CANISTER FILTER!!!! unless you want to replace the impeller over and over again.... you can install it on the input side on a HOB type filter because they are fairly cheap in comparison... just my opinion??? canisters and the parts are $$$$$$

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  21. Isn't two cups of sugar, too much sugar? Two cups of sugar is almost a soda can of sugar. I think that's too much sugar. I use only about half a cup and I get close to 3 weeks worth of CO2. I never used Baking Soda before, but I'm going to give it a try today.

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  22. I use a chainsaw canister. The gas chamber as yeast reactor and the oil chamber to wash the CO2 and hold back foam by bubbling it through water. My recipe is:

    4l water
    750g sugar
    1 pack of dry yeast

    First activate the yeast with a 1dl of water and a hand full of sugar in a small container. Add the sugar to the tank and add the 4l water but don't mix it!

    Once the yeast starts to smell like living yeast and foam is forming add it to the chainsaw canister and screw on the lid.

    I don't mix the sugar with the water because I like to flatten the spike in CO2 production at the beginning to archive a longer production time. With this method I get about a month worth of CO2 at normal temps and 3 weeks in the summer at 30°C.

    Regards, Dominik

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  23. this is helpfull..tnx very much..:-)

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  24. I use an UP CO2 diffuser on the output line of my filter and 2 x 2litre coke bottles, works excellent and plants growing nicely.

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  25. Hi people,
    Here is a mix that will give you near a month of co2 production:
    6 full table spoons of sugar
    3 full spoons of starch
    1 full spoon of baking soda
    1.5 litters of aquarium water

    Boil in half the water for 15-20 minutes,when it becomes a sort of jelly cool down.

    when cool down add a teaspoon of wine yeast dissolved in 20mml of warm water

    add one teaspoon of nutrafin plant fertilizer
    add one teaspoon of uncooked rice.

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  26. ok ive read this hole page im going to try this a 2 liter with a check valve at the top and the only thing i could find was wood filler to seal it. im also put a splitter at the bottom of the hose with 2 air stones and im gonna cut the bottom off of a water bottle to catch the o2 thx 4 the info

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  27. how much water do i use exactly? i dont have any o2 bubbles i think i have to much water.

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  28. If you would like a PERFECT seal then take your cap to a local tire shop. Ask a tech to drill a hole in it and put a valve through. Make sure you ask them to remove the valve stem though. Many years ago I used to work at Discount Tire and we did it for fun. Hope it helps!

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  29. The baking soda does not expedite the process of fermentation, but rather keeps the yeast making co2 longer. A byproduct of yeast fermentation is alcohol, and alcohol is acidic - causing the pH of the water to become acidic and kill the yeast. The baking soda acts as a buffer to this process so that the yeast stays alive longer.

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  30. Re earlier post: quote: " September 12, 2010 7:11 PM
    Anonymous said...

    Hi people,
    Here is a mix that will give you near a month of co2 production:
    6 full table spoons of sugar
    3 full spoons of starch
    1 full spoon of baking soda
    1.5 litters of aquarium water

    Boil in half the water for 15-20 minutes,when it becomes a sort of jelly cool down.

    when cool down add a teaspoon of wine yeast dissolved in 20mml of warm water

    add one teaspoon of nutrafin plant fertilizer
    add one teaspoon of uncooked rice."

    Can someone tell me why the starch, rice and fertilizer are necessary?

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  31. I've been using this formula for over a year now with great results--however, this last batch is not doing a thing using the same formula. Any ideas? I checked my tubing and everything is airtight, the check valve is clear, no obstruction, etc. My only guess is the yeast has lost something, but it's good until 2013 according to the label and has been kept under refrigeration since I bought the bottle around April of last year. Thanks for any suggestions as to why this is happening! Michael

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  32. Thanks! 3 weeks of CO2 and still going strong.

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  33. Baking Soda is not for a "catalyst" - it is a buffer to help keep the pH of the mixture from dropping too quickly, killing off the yeast.

    I have mixed my DIY generator both with and without - the baking soda being the only variable - and every time I have put it together without the Baking Soda, the yeast quits far earlier (nearly half the time as with).

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  34. Hi all

    Can anyone offer any advice?
    I have tried this but only using a 1 Litre bottle (for Co2 generation) which goes into a smaller bottle (acting as a seperator and bubble counter combined). Then a single tube running up to a small section of Bamboo chopstick wedged into the hole at the far end.(Acting as a Diffuser).

    As I am only running a 1 litre bottle, I simply halved the amounts of each of the suggested ingedients.(Minus ANY Baking Soda, as I have a normal tap water PH of approx 7.6, so it's not needed?)

    Anyway... everything looked great soon after the initial mixing and setting up, with Co2 bubbles flowing into the seperator/bubble counter steadily after only about 15/20 mins.

    However, even after waiting about 24 hours, I cannot get the pressure to travel all the way up the tubing to reach the diffuser. Even tho, the bubble-counter continues to show gas that far in a continous amount??

    The tubing (from the bubble counter to the diffuser) is one single un-cut section. So should not have any places to be passing or leaking. I have put the diffuser into a large glass of water (whilst checking every thing out) and I can see that the gas/air seems to have travelled about 90% of the length of the tubing, but just doesnt seem to have enough pressure to flow all the way, out of the diffuser.

    I have even taken the diffuser off completely, to see if it make any difference, but the same thing just keeps happening.

    PLEASE let me have any ideas? =)

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