DIY CO2 Made Easy

I've seen quite a few posts and questions concerning DIY CO2 setups and having issues. I'm not going to say that mine is bullet proof and your results may be different. I can say that so far, this one has never failed me and it lasts a good (4) weeks plus. This is monitored by use of drop checkers. So I thought I would post my write up out here in hopes that it may help people in the future. So here it is.


Many hobbyists like to have natural plants in their aquariums. Depending on factors such as lighting and the types of plants you keep, you may need to add CO2 to your system. However, buying a pressurized setup can be a bit costly. In comes DIY (Do-It-Yourself). Even then, some people think that even this method is cumbersome. Well, here we are going to go from start to finish just to show how simple it really is.

Step I: Making the medium (a.k.a Jell-O)
............. Ingredients: 1 pk. Regular 6oz Jell-O. Flavor Optional.
.............................. 2 ½ cups boiling water
.............................. 1 ¾ - 2 cups pure cane sugar
.............................. ¼ cup uncooked rice (optional)

............. 1) In a large saucepan, fill with water and bring to a rolling boil.
............. 2) Empty (1) 6oz package of Jell-O in a large mixing bowl.
............. 3) When water is boiling, carefully measure out 2 ½ cups.
.............................. a. CAUTION: Contents will be very hot. Be Careful.
............. 4) Pour water in bowl with Jell-O and mix thoroughly until well dissolved.
............. 5) Pour in sugar and thoroughly mix again until well dissolved.
............. 6) Once everything has been dissolved, pour contents in a flat Tupperware container.

............. 7) Cover and place in refrigerator.

* Optional Step *
After about two hours in the fridge, the Jell-O should be starting to set. Test with a grain of rice.
- If it sinks to the bottom, it's not firm enough. Place back in fridge and retest later.
- If rice sits on the top or sinks slightly, it should be good enough. Make sure however that Jell-O is still in a liquid state.
- Sprikle 1/8 cup of uncooked rice over the Jell-O. Using a spoon handle or similiar, gently stir the rice into the Jell-O. It should be free floating within the Jell-O
- Place back in fridge to finish setting up.

Step II: Making the Reactor
............. While the Jell-O is setting up, let’s make the reactor vessels.

............. Materials: 1 64oz Juice bottle (Ocean Spray seems to be best)
........................... 1 20oz Gatorade bottle
........................... 4’ CO2 tubing
........................... GE Silicone I caulk (optional but recommended)
............. Tools:..... Cordless drill w/ bits
........................... Scissors
........................... Case Knife
........................... Needle Nose Pliers
........................... Toothpick
........................... Giant Peep Assistant (optional)

............. 1) Start by thoroughly cleaning both bottles with hot water.
............. 2) Remove lids. Drill a 3/16 hole directly in the center of the juice bottle lid. Drill two holes in the smaller water bottle lid.

............. * NOTE * For best results, start with a small drill bit to create a pilot hole. Then using other bits, work your way up to 3/16. The 3/16 size is a fraction smaller than the diameter of the tubing and will provide for a tight fit.

............. 3) Using the case knife, carefully trim any shavings left by the drill bit.
............. 4) Measure about 2’ of tubing.
............. 5) Using scissors cut one end of the tube at an angle.


............. 6) Push the angled end through the top of the cap.
............. 7) Using the pliers, grab the end and carefully pull the tubing the rest of the way through the cap.

............. 8) Cut off the angled end to make a flat cut.
............. 9) Slowly pull tubing out of cap until about ¼” remains in the cap.
............. 10) Repeat steps 5-8 with the opposite end of the tubing into one hole of the water bottle cap.
............. 11) Test fit tubing in water bottle and adjust length if needed. There should be a bend in the tubing.

............. 12) Using the remaining length of tubing, repeat steps 5-9 using the second hole on the water bottle cap.

............. 13) Caulk around all three pieces of tubing on the inside of the caps using GE Silicone I caulk only. This is an optional step as the seal around the tubing will be sufficient with the 3/16” hole depending on how you diffuse the gas. I didn’t do this at first until I switched to a glass diffuser, which resulted in higher pressure build up. In one setup, I discovered a leak in the separator bottle so I added the silicone. Caulk around the tubes on the top side as well.
............. 14) Use the toothpick to spread the caulk completely around the tubing to ensure the entire area is covered.

............. 15) Set caps aside and let silicone cure at least 24hrs.

Step III: Time to make gas
............. Now that our Jell-O has set and our reactor vessels have been made, it is time to start making gas… CO2.
............. Ingredients: ½ tsp. Bakers or Brewer’s Yeast divided (¼ tsp. for initial setup / ¼ tsp. to add later)
.............................. 1 tsp. Sugar
.............................. 1 cup hot water
.............................. ¼ tsp. Baking soda
.............................. Air stone (diffuser)
.............................. * NOTE * use a limewood airstone or for best results, use a glass bell or nano diffuser
.............................. * NOTE * I only use Brewers yeast at the moment as I have found it lasts longer than either Fleischman's or Red Star baking yeast. Again, results may vary.

............. 1) Activate the yeast. In 1 cup hot water, dissolve 1 tsp sugar. Stir thoroughly.
............. 2) While water is still spinning from step 1 (tornado effect as I like to call it), carefully pour in ¼ tsp. of yeast. This will help in prevent clumping.

............. “snow globe” effect shows the yeast activating:

............. 3) While this is activating (appox. 15 minutes), cut Jell-O in small cubes. The small cubes allow for more surface action for the yeast.
............. 4) Add the cubes to the large bottle.
* Optional Step *
- Using the remaining 1/8 cup of uncooked rice, layer it between the Jell-O. Do this by adding a few cubes of Jell-O to the bottle and then sprinkle a small amount of rice on top. Repeat this process until all rice and Jell-O has been added to the bottle

............. 5) After yeast has activated (again allow approx. 15 minutes), add 2 cups hot water to Jell-O bottle.
............. 6) Pour yeast mixture into bottle.

............. 7) Add ¼ tsp Baking Soda.
............. 8) Using hot water, fill bottle until you have approx. 2” free space from the lid.
............. 9) Add remaining ¼ tsp yeast.
............. 10) Fill seperator bottle with water about 3/4 full. Water should be over the end of the curved tubing. This will enable you to see and count the bubbles.
............. 11) Cap both bottles tightly. Remember to allow for a “curve” in the separator bottle.

............. 12) Within hours, you will start to see generation of CO2.


That’s all it takes. Now go grow beautiful and healthy plants.

******************
* EDIT *

This write up is a little old now as in the pictures you see a standard water bottle being used for the seperator bottle and a limewood airstone for the diffuser. Both of these have since been replaced with the Gatorade bottle and glass diffusers respectively. I just haven't taken updated pictures to show those.

nice guide.

Great write up.

Way to go. Nice write up.

thx....now let's get them plants growin. LOL

Welll done!

I think even I could do that! Next Q.. how often do you treat each tank?

when the lights come on till the light go out you have it running. mix lasts anywhere from 2 weeks to 6 weeks. (i think it's the freshness of the yeast myself)

So your saying that you'd be feeding Co2 non-stop?

While the lights are on only. You turn it off at night as the plants only absorb CO2 in light. If you want a DIY set up I have an extra one. Do you have a powerhead thats works?

Nope.. I've never even paid the slightest attention to your set-up.. sold two power heads at the auction... still weighing the benefits of using Co2 or natural growth.. Strikes tanks and yours do push me in that direction though....

I now just use Flourish Excel. Just easier for larger tanks.

Im'a thinkin I've got enough on my plate right now without adding in a Co2 regimen.. Thanks for the Co2 set-up offer though.. Still haven't done the brine shrimp hatching !

williemcd wrote:

So your saying that you'd be feeding Co2 non-stop?

You would be running this non stop. Only in a DIY set up though as unless you build a bullet proof container, you don't shut it off.

Larger tanks really won't benefit from DIY unless you're running multiple bottles which can then get cumbersome. Pressurized is the way to go at that point. Then you would employ the use of a solenoid and run your CO2 on a timer.

Also, DIY CO2 is pretty much a "set it and forget it" type of thing for at least two weeks. Once you set it up, just let it do it's thing until time to change bottles. Once you get it down, it takes only minutes to swap out.

Great write up with a get pictorial! I used DIY Co2 for awhile and saw some results the difficulty comes when you try to diffuse the CO2. Most of the nice glass type unit over accept pressurized CO2. I used a gravel snake and power head method and it worked well BUT the plants nearest the diffuser got most of it. It is hard to reach a surface area large enough to exchange the CO2 at a rate that will increase it in the whole tank.

You can shut off DIY CO2 at night BUT as James said you want to make sure your bottles can handle the pressure build up otherwise you will end up with yeast splatters all over the wall haha.

I turn off my pressurized system an hour before the light go off. This just helps save gas and the PH swing during the night is minimal and none of the fish mind. I don't have much surface aggregation though so it drops only through surface exchange. When you inject large amount of CO2 shutting it off at night is a must or you would have to replace the bottle all the time haha.

I agree, great write up. I loved the giant Peep!

Thanks!

The peep was a tough one to work with. He is so bossy!

Nice write up I really like the DIY bubble counter. Even pressurized systems there is some talk that CO2 should run constant due to the pH drop when CO2 is not being pumped...Great pictures great write up....

One Question...do you use check valves? Had a CO2 stop on me (bad batch of yeast) and ended up siphoning water from the tank to the bottle.

I would always use a check valve. That is $2 that will save you so much hassle "just in case"

I personally don't use them.

Ok was just checking seems they obstruct alot of airflow...I will have to hook up some bubble bottles and see how they work once again good info thanks

They shouldn't really obstruct much flow the CO2 system is really under pressure even in a DIY system. The main thing is in a DIY CO2 is the pressure has to get high enough to "open" the valve which is really next to nothing and if you squeeze the bottle one time it will be open anyways.
The bubbles come out depending on the pressure behind them. With a DIY you would normally have no control over this unless you sent the CO2 through some type of needle valve. The check valve once in the Open position should not impede anything as the CO2 does not really "flow" but slowly leaks under pressure.
In any case like I said before it is a small/cheap safety system for any setup. If you where to use a pressurized system it really is a must have as if water reaches the regulators it corrodes them very badly. On a DIY worst case is you end up with a tank full of yeast. The way around that of course is to build a gas exchange bottle but even that is not fool proof.

and when your done, you have alcoholic jello shots. well done! lol =)

the jello recipe works, I use it and I'm on the 3rd week on it.