Making A DIY C02 Unit and C02 Mixture Article

depthC

Superstar Fish
Feb 24, 2003
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#1
Since DIY C02 is a pretty popular method of injecting C02 into small tanks 30 gallons or less I've made an article to help anyone in the process of making a C02 unit. So lets just get right into it.

First were going to need a few things to make the unit. These include:
- A drill
- A few feet of tubing
- A pair of scissors
- A sealant
- A checkvalve (optional)



Now first you have to take the drill and find a bit that is just a little smaller then the diameter of the tubing (the kind of tubing you choose does'nt matter much, I used silicon because it has a little more resistance to C02 and will last a little longer than the normal clear tubing, but its fine if you choose the regualr tubing). Then cut the tubing down to the size of which it will be ran to your tank, also make sure to leave some loose tubing just incase you need to resituate the bottle or anything else dealing with the length of the tube. Then drill a hole in the center of the cap and fit the tubing in as snug as you can get it. Only put the tubing in 2-3 centimeters. After this is done you are ready to seal the cap.

So now bust of the sealant and get some in the cap against the tubing to make a secure seal. Let it sit for 30 minutes to an hour for it to dry somewhat. Then repeat the same thing for the top and let it sit. After your done sealing the tube don't mess with it much because it may move the tube and make it a less secure seal.

- Sealed Bottom
- Sealed Top

Now you may want to wait a full day just to make sure your sealant is fully sealed. Don't be impatient you'll probably end up resealing it if you do put it to use too soon.

By now you have finished making the C02 unit and you are ready to make the C02 mixture. This is what the end product should look like:



But before we jump right into making the mixture lets talk about methods of Diffusion.

There are tons of methods to diffuse the C02 into your tank. To list just a few there are:
- C02 Bells
- Diffusion Unit
- Injection into a Power Filter
- Airstones

Of course there are more but I dont want to get that detailed into the diffusion. If you are running a power filter just stick the tubing into the intake and the impellar will dissolve the C02 very well. Another easy method is an airstone, but let me tell you from my experience that it is a poor method and most of the C02 does'nt dissolve into the water. So I'd stick with the filter intake method it works great.


How To Make the C02 Mixture

Okay now to make the mixture we need a few things:
- The 2L Bottle
- Sugar
- Yeast
- Measuring Spoon
- A funnel



I use the mixture of 2 cups sugar and 1/2 tsp of yeast. There are other mixtures and they have other affects. More yeast means the mixture will produce a lot of C02 but not last as long, as the yeast eats the sugar and a biproduct is the C02. So with this 1/2 a tsp it produces a constant C02 for a longer period of time, I would say for 3 weeks and the 1 tsp mixture lasts 2 weeks or less. Whatever you choose is fine, but I recommend the 2 cups and 1/2 tsp yeast.

Now take the bottle set the funnel in the top and get ready to pour in some sugar and yeast (you could use a piece of paper for a funnel if you dont have one, but i fortunately found one around the house). Now add the 2 cups of sugar, and the 1/2 tsp of yeast. Then its time to add the water. To get a good start of C02 production we want to use luke warm water, dont use hot water because this will kill the yeast. Fill the bottle with water up to the brim were it starts to curve into the top. Im not sure how to explain this that well, but just leave a 3" gap between the water level and the top.

Now you have the 2 cups of sugar, 1/2 tsp of yeast, and the water in the bottle. Find a cap and shake up the mixture well and then let hook it up to your sealed cap which should be hooked up the tank in your diffusion method that you chose. Dont leave the undrilled cap on the mixture and forget it, you will come back to a huge mess, remember this produces C02 and if its not left a point to exit it will turn into a bomb. Now that its hooked up it should take and hour or two to start producing. It may take a day depending on the temperature of water you used and if the yeast is active. Also remember to shake it up everyfew days to keep the unit producing C02.

Alrighty, you now should have a DIY C02 made up and the mixture producing. I hope this helps out anyone looking to make a cheap C02 unit. Good luck!

- depthC
 

depthC

Superstar Fish
Feb 24, 2003
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#5
Baking Soda is used as a buffer to keep the carbonated hardness up so the pH doesnt crash. In his case he had a real low pH so it was needed and i guess it made his batches last longer. Give it a try and tell us if it works.

- depthC
 

depthC

Superstar Fish
Feb 24, 2003
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#6
Well i got my article posted up on PlantedTank.net . I posted it in the DIY section and the webmaster asked to use it and ofcourse i said yes so here it is on his site.

http://www.plantedtank.net/co2.html

Also check out their forum its a great forum and ive been reading and posting there lately. K just wanted to share my accomplishment.

- depthC
 

depthC

Superstar Fish
Feb 24, 2003
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#8
Ahh well i havent really worked with a smaller tank then a 10g, but with 3 wpg which is a good amount of light id suggest 1/4 tsp of yeast and 1.5 cups sugar. It might be the same as a 10g which could be 1 tsp or 1/2 tsp yeast and 2 cups sugar, but im unsure if the amount of C02 in a 10g setup Diy would be too much for a 5g tank. So if it was my tank id try a 1/2 tsp yeast and 2 cups sugar with fish just to see if they can handle that much C02, if they cant cut back on the yeast and this should make it produce less C02 and for a longer period. This is my opinion and maybe someone with a 5g setup can add to this but the only real risk could be suffocating your fish.

- depthC
 

werebot

Medium Fish
May 20, 2003
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#10
Excellent thread DepthC,
I was just wondering about the temp of the water.
It seems that with the system I put together the water cools down abit then just looks cloudy. Not a single bubble.
I have noticed that when I make beard you should keep the dough in a luke warm area for the best rise.
Is that true with a DIY CO2 System?
Should I try and insulate the bottle(s)?
Just curious and a little frustrated.
Thanks.
 

depthC

Superstar Fish
Feb 24, 2003
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#11
Well temperature does matter. How cold does it get in your house? In the summer my room gets pretty cold at night and my C02 still produced and my fish still lived w/out heaters. So it should still produce C02, but its true you should keep the yeast warm so it produces a steady flow of C02. Also the mixture should look cloudy. Mine looks cloudy for almost 2 weeks then its turns clear but even when its clear it produces C02 but not at a steady rate. You could try to insulate the bottle, im unsure of how much this would help but its worth a try. Also if you do, remember to post back with the results. Im still learning and by no means am i a expert on DIY C02 im just trying to provide useful info to those that need it.

- depthC
 

werebot

Medium Fish
May 20, 2003
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#12
Hey DC,
Me too. And save some $$$$.
I will shirley(surely?) keep everyone current.
Winter is coming so it will be perfect for experimenting.
I'll see if the water clears up first.
Maybe it has been working and I have been looking for the wrong thing.
Is there anyway to tell if it is working?
Or will my plants just go nutty?
Thanks.
 

depthC

Superstar Fish
Feb 24, 2003
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#13
Uh, yeah there is a definate way to tell if its working. How are you injecting it into your tank? If its producing bubbles thats how you tellif its producing, it doesnt matter how the bottle looks. If its not producing bubbles make sure you seals are tight and u have the cap on tight enough. Also it may be your yeast that is inactive. But dont resort to that yet because its very doubtful.

- depthC
 

werebot

Medium Fish
May 20, 2003
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#15
I'm using a plastic bell down in the corner of the tank. I'll keep a closer eye on it.
I made clips to help seal the possible weak points.
I want to try and keep the hoses as short as I can, but if I have to I'll try the heated bucket method.
 

Lotus

Ultimate Fish
Moderator
Aug 26, 2003
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#16
Yeast works best between 75 and 85 F (that's the optimum). Below 70F it will still produce, but at a lower rate.

The easiest way to check the effectiveness is to measure your PH and KH, then use the CO2 chart to see if you have the right amount :)
 

Somonas

Superstar Fish
Oct 22, 2002
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#18
I have a comment re: recipies

I have been using 1/4tsp/2 cups for the last couple months, 2x 2L on a 33. I seem to be running out of co2 at the end of the month even alternating a week between refills. Might go back to 1/2tsp alternately 3 weeks.
 

depthC

Superstar Fish
Feb 24, 2003
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#20
Im not sure of the difference between diffusion between one big bubble or a bunch of tiny bubbles from a airstone. Either way there isnt much diffusion going on when the C02 bubbles rise to the surface so i dont think the airstone will be effective.

The most simple method i can suggest to you is to inject the C02 into your filter so it can chop up the C02 bubbles and trap some to diffuse. What kind of filter are you running on your 55g tank? If its a powerfilter just pop the tube into the filter intake tube and youll be able to hear to bubbles churning in the filter. I use this power filter injection method and it works nicely so i can only speak highly of it since ive had only good results. But if your using a canister filter there are some models that can cause some troubles.

- depthC