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DIY CO2 Guide with Pictures & Recipes

391K views 160 replies 71 participants last post by  stigigemla 
#1 · (Edited)
Overview
DIY CO2 is a matter of taking Yeast and Sugar, and mixing them with water to create a reaction by product of CO2 gas. This works extremely well for 1-30 gallon tanks. For larger aquariums you must use more DIY bottles to increase CO2 output. It requires more effort, and most tend to go over to pressurized because the time and effort, and added cost over time required. But it can be done.



Equipment:
1. Gatorade, Apple Juice, or Oceanspray Bottle
2. 2 Cups of Sugar
3. 1/4-1 teaspoon of yeast
4. 1/4 teaspoon of baking soda (optional)
5. Diffusor: Hagen Ladder, sweetwater AS10, or through filter intake

Recipe:
1. 2 Cups of Sugar
2. 1/4-1 teaspoon of yeast (more yeast = faster reaction = more CO2 for shorter time (2+ weeks))
3. 1/4 teaspoon of baking soda (optional)

Making the Canister (Reaction Bottle):
1. Take drill bit or hammer and a small nail (smaller than the diameter of tubing).
2. Unscrew your cap, hammer/drill the nail into the cap to make a small hole
3. Get some Airline tubing and pull it through the small hole with pliers.
4. The small hole will create a seal around the tubing so no need for glue, hence the extra small hole.

Adding the Recipe:
1. Add 2 cups Sugar
2. Fill the container with water up to 3/4 way.
3. Add 1/4-1 teaspoon yeast
4. Add 1/4 teaspoon (baking soda)
5. Put the cap on and twist it on tight.

Diffusion Methods
1. Line directly into the intake of your filter,
2. Limewood Diffuser
3. Sweetwater stone AS10
4. Hagen ladder
5. Glass difusser



Wait a few hours and you got CO2

Special Notes:

Check Valve Prevention System + Yeast Strainer
In order to keep the Yeast Muck from being released into your tank, A bubble counter or separator is used to catch the muck. This DIY bubble counter also provides a check valve system to prevent water from back siphoning out of the aquarium.

A Syringe from Rite Aid, Long Drugs, Walgreens, etc, can be paired with a standard plastic check valve to make this DIY bubble counter.

1.Take the plunger off
2. Add some glue to the check valve
3. Insert check valve and dry for 24 hours.
4. Once dry, the tubing will fit on the end of the check valve, and at the end of the syringe nozzle.
5. Insert this between the diffuser and your reaction bottle.



NOTE: Some plastic check valves occasionally don't work, always check your valve when replacing the DIY CO2 mixture. CO2 will degrade plastic valves over time, so always check.

For Larger Tanks
For larger tanks, and those that need to lower the ph more with more CO2 output. Using multiple diffusers placed at each side of the tank (left, right, middle, etc) will increase CO2 dissolution. In addition, you can add a T-valve to connect multiple bottles and to own diffuser to produce more out of your diffuser. Here is an example. Placing the diffusers under a current will blow the CO2 around and further increase CO2 dissolution and contact time with the water.

Is it working?
You should see bubbles coming out within 4-24 hours. To see if your CO2 is being properly dissolved based on whichever diffusing method you chose, test your Ph before adding CO2, and after adding. You will see a drop. Refer to a PH and KH chart to see what your levels are at in ppm.

This reaction will last at least 2 weeks to 4 weeks. The more yeast added the faster the reaction but shorter duration.

Be careful, and enjoy your CO2.

-John N.
 
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#2 · (Edited)
It's really not difficult at all! It really only takes about a half hour at the most, and that's mostly for setting up "the hardware". When you get used to it, it takes maybe 5 minutes to dump the old yeast, wash the container, fill it up with the new yeast & sugar. However, you may want to add a gas seperator, which helps to reduce "gunk" that you may get from DIY Co2. It's simply an empty bottle between the yeast bottle and the aquarium. see here:
http://www.qsl.net/w2wdx/aquaria/diyco2.html

Don't be intimidated :D :thumbsup:

And great job John. Nicely done how-to. I think I'll have fun making the bubble counter...
 
#3 ·
I really appreciate seeing photos. My experience with yeast is in making bread and I always had an image of the yeast mixture that I use in baking. I had a hard time imagining the ratio of yeast to water and thought you were dealing with a much thicker mixture. This helps a lot.
 
#4 ·
:help: This is the one section that I don't get/understand completely.
- Is there an illustrated/cartoon guide available for idiots like me?
- In which direction does the check-valve go? Does it matter?
- Is silicone sealant/glue needed to hold the air-tubing in place?
- Does it matter whether I use silicone air-tubing or "the normal stuff" (clear type)?

Thanks!

John N. said:
Check Valve Prevention System + Yeast Strainer
In order to keep the Yeast Muck from being released into your tank, A bubble counter is used to catch the muck. This DIY bubble counter also provides a check valve system to prevent water from back siphoning out of the aquarium.

Go to Rite Aid or Longs Drugs and pick yourself up a syringe and find a check valve at your fish store.

Take the plunger off, add some glue to the check valve, insert it where the plunger used to be. Fill the syringe halfway with water. The tubing will fit on the end of the check valve, and at the end of the syringe nozzle. Insert this between the diffuser method and your reaction bottle. Congratulations, you've made yourself a bubble counter and a check valve system for your DIY CO2.

Some plastic check valves occasionally don't work, always check your valve when replacing the DIY CO2 mixture. CO2 will degrade plastic valves over time, so always check.

-John N.
 
#5 ·
Thanks for this guide. I've been running a DIY CO2 on my 23g for a month or so and have gone through 3 different mixtures (1 cup sugar + 1/2 tsp yeast, 2 cups sugar + 1/4 tsp yeast, 2 cups sugar + 1/2 tsp yeast) to try to find an ideal one. So far I've only been able to get a maximum of 15-20ppm CO2 out of it (in the first week), and the level starts to go downhill by the end of the second week (as indicated by the slower bubble rate in the bubble counter).

Questions:
- Do you find it helpful to dissolve the sugar first? I've been dissolving the sugar in hot water, let it cool to lukewarm, then add the yeast. Not sure if this really matters. I only use 1L of water BTW, since the container I use (from Red Sea Bio kit) only holds 1L.
- I've heard that some people shake the bottle every few days to help reinvigorate the mixture. Truth or myth?
- Does adding baking soda help the CO2 output level or only duration (i.e. lasts longer)? I'm thinking it might, especially in a highly concentrated mixture like I have (due to less water used).

Thanks in advance!
 
#6 · (Edited)
Syringe Bubble Counter

Check valve goes like this: 2L juice bottle - tubing -check valve-syringe - tubing to diffuser inside tank.

The check valve should go in the direction that allows CO2 gas from bottle to enter the aquarium. You can blow through it to make sure it's facing the correct way.

The tubing will fit directly on the syringe output and also on the check valve, so no glue is needed there. Only glue is needed where the check valve and syringe connect.


(picture from a member on another forum).

Either tubing will work, silcone will get brittle over time, normal vinyl tubing will get harder over time. Both will need replacing once you see that it does or they system starts to leak CO2. This time can be a period of 3+ months before needing service.

-John N.
 
#7 · (Edited)
Hi Upikabu,

No problem, the guide was something I looked for when I started, and I was having a hard time grasping the concept, so pictures definately help. And so hence the creation of this guide to help others.

As for your questions, I do stir my sugar and try to dissolve some of it when I start. I never did it with hot water, just luke warm. I noticed a slight increase when it first starts, but it the bubble count balances out over time.

You'll get a better output of CO2 if you use a larger bottle.

Shaking: It helps, since it's dissolving and mixing up the sugars and yeast. But again, it doesn't make a noticable difference in the long run in my experience. I don't recommend it since the liquid can hit the inside tubing, and get some yeast muck in your tubings.

As for the baking soda. It's to raise the KH and stabilize the reaction if you have low readings of KH in the water you are using. I stick a little in there, every time, since I have a KH of about 3.

My advice try it without baking soda, and once with it, and see if you notice a difference. It doesn't hurt the reaction.

-John N.
 
#8 ·
Hi John,

Thanks for the explanations. My KH is 5 out of the tap, so baking soda probably won't have much effect in my case. Mixing may not help either, as the sugar and yeast were already dissolved from the get-go.

What's the highest level of CO2 that you (or anyone else) were able to achieve with one 2L bottle of DIY CO2 in a 20g?

Cheers,
-Paulus
 
#11 ·
For the Hagen Nutrafin Canister:

Sugar to the bottom inside line,
Water to the top inside line,
1/8-1/4 teaspoon yeast
1/4-1 teaspoon baking soda

Close as tight as possible and enjoy.

The placement of the hagen should be under good circulation as to spread the dissolved CO2 around, and maybe catch the escaping bubble. Not to worry about catching that bubble, since the bubble gets about 85-95% smaller as it travels the rungs, giving you very good dissolution.

-John N.
 
#12 ·
John => Thanks & dah! I should have thought of blowing through it to make sure it faces the right direction. The picture is a nice help though too.

re. tubing, I was at a local aquarium club (LAC) talk a while back where the speaker recommended the silicone tubing over the clear vinyl (according to my notes), but I could not remember why so. SO thanks for the info on both kinds.

re. baking soda and limiting/controling the reaction, it does seem that many municipal water sources are hard enough. As I remember it, alcohol, which is produced by the fermentation process (that we are using to supply DIY CO2), is the more limiting/controlling factor. Affecting the constancy more and even killing the brew over time.
 
#13 ·
More than enough

upikabu said:
Hi John,

Thanks for the explanations. My KH is 5 out of the tap, so baking soda probably won't have much effect in my case. Mixing may not help either, as the sugar and yeast were already dissolved from the get-go.

What's the highest level of CO2 that you (or anyone else) were able to achieve with one 2L bottle of DIY CO2 in a 20g?

Cheers,
-Paulus
I have a 37 gal tank and a 2 litre bottle DIY system. I generate so much co2 that I have to run a bubbler at night to keep my fish from being aphixiated. However, the secret to getting a higher CO2 rate is in how well the bubbles are smashed up as they are released. The smaller and more numerous the bubble are the higher you co2 concentration will be. The goal is to reach about 30ppm of co2. I have no trouble reaching and exceeding that.
 
#15 ·
On the Hagen Nutrafin ladder, I tilt the ladder to trap the bubbles. I figure, why waste them. If I could figure out how to get a nice looking (clear) cup like thing to go OVER the bubbler and trap them for good I would.

Then they would dissolve 100% - correct?

:yo:
 
#16 ·
Can you guys show a link to a nice CO2 Bell?
The link to the Glass Difussers is great. Good price too.

I think a Glass Diffuser with a CO2 Bell somewhere above it would look really cool!
 
#18 ·
For me using the above recipe in the nutrafin canister, it lasted for about 2-3 weeks. It probably could go longer, but I like to have it going at the peak performance.

Using a Juice or 2L bottle, the reaction and bubble count was longer at about 3-4 weeks.

-John N.
 
#20 ·
Yeah, I am tried those for a day. Ended up putting the Nutrafin Ladder back in for now. I do notice the size of the bubbles do get smaller before they finally escape from the top. Boy, watching your whole tank pearling is a trip!
 
#21 ·
Found the checkvalve in the Local Fish Store. $2.00
From the otherwise very good directions, I thought I had to create that also. This should be easy now!
 
#23 ·
harbisgirl said:
Hello,

I'm new, forgive me if this is a ridiculous question :)

I have a sand substrate, would it work to stick the tube under the sand to diffuse the bubbles?
Interesting idea, but probably no, since a large bubble will still come out of the sand and rush to the surface. The key for getting CO2 in your tank's water is to have the CO2 gas bubble in maximum contact with the water so that it can dissolve. For example, the hagen ladder does this very well. The bubble travels up the ladder getting smaller as it goes up. Similar to this type of glass diffuser that New Guy has. See the cool video in post #10 of

Other options is to have the impeller of your filter or powerhead chop up the bubbles. So feeding the line directing into the intake of your filter wlll maximize the surface area of the tiny bubbles that get chopped up, and provide better chance of dissolution.

-John N.
 
#24 ·
Strange I was expecting at least one person to mention using High Tolerance Champagne or Wine yeast as it can tolerate almost 3 times the Alchohol % of bread and beer yeast, aslo using sucrose instead of sugar, and adding the sugar in incremants per week and not a huge dose up front allows the brew to ferment at a more consistant rate, also have two of these bottles running so that as one finished the next one has finished its really busy inital phase and has settled down so the tank has a nice consistant suppy of CO2
 
#25 ·
I have a question about bottle size...from what I've read using a 2L bottle vs. a nutrafin canister will last longer due to the decreased alcohol concentration levels. My question is about the peformance of the 2L vs. the Nutrafin canister. Basically, which will produce the greatest amout of CO2 a day? My current mix in the Nutrafin canister is lasting right at two weeks, so if the 2L will produce CO2 at the same rate, and last longer, I'd like to switch. However, since I'm running the system on a 29G I want to have the highest possible rate of CO2 production, even if that means starting a new batch every two weeks vs. every 3 or 4. Thanks for the advice!
 
#26 ·
It's really all dependent on how much yeast and sugar is supplied in the bottle. Since the 2L bottles types can hold more of both, the reaction will be last longer, and have a higher production rate in the short term (2 weeks) if supplied with more yeast (3/4 tsp).

You'll see an longer reaction, and increased CO2 production if you switch to the 2L bottle, and add a larger amount of yeast than recommended. This will shorten the life span of the CO2 from 3-4 weeks to 2 weeks, yet production will be dramatic more.

As Sean stated, wine yeast will also enhance the life of the reaction.

I recommend using (2) 2 liter bottles T-ed together for maximum CO2 production.

-John N.
 
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