Instructions for Setting up a DIY CO2 System

I have been asked how to set up a DIY CO2 system a lot lately, so decided to create this thread to use as a reference.

For starters, there are several videos found on YouTube explaining how to set up a CO2 system. Here are the steps I take.

Supplies
*2-liter, or larger bottle(s) for CO2 generation/reaction - The number of bottles depend on the tank size. I use one bottle for every 10-20 gallons of tank size. In my tanks I use 2-liter bottles and have 2 bottles on a 25G tank; 4 bottles on a 55G tank; and 8 bottles on a 90G tank (I do not recommend DIY on a tank this size. It is a lot of work; requires a lot of space; BUT it can be done with diligence)

*One 20-ounce bottle used as a bubble counter and as a filter between the yeast and the tank

*CO2 airline tubing. There is CO2 specific tubing to ensure no leaks; but I have used standard airline tubing in a pinch

*Check Valve to guarantee that the tank water cannot backwash into the system

*A variety of tees, couplers, adapters used to join tubing as needed. I purchased a set like this

*Apply 100% pure silicone on the outside of each cap, around the tubing lines, to ensure no leaks in the bottle caps. Optional.

Tools Needed
Anything you have around that can drill a hole into the bottle caps and to pull the tubing through the holes. When I didn't have a drill I used a large nail to get through the plastic bottle cap and then used a phillips screwdriver to enlarge the hole.

Preparation Steps
*Rinse out each bottle with hot water. Do not use soap.

*Drill a single hole in the bottle cap of each 2-liter bottle. Each hole should be just large enough for the tubing to fit snugly

*Drill 2 holes in the cap of the 20-ounce bottle. This can be a bit tricky as too much pressure on the bottle cap can crack it and make it difficult to create an airtight system. If this happens, get another 20-ounce bottle and attempt to drill the cap again. I broke the first 2 caps I tried to drill 2 holes into.

Inserting Tubing
*Cut a length of tubing long enough to allow ease of working with each bottle in the entire system. I recommend cutting tubing at least 12-inches as it's easier to shorten then to lengthen them.

*Cut one end of the tubing at a sharp angel to make it easier to insert into cap. I use a pair of needlenose pliers to pull the tubing through as it is a tight fit.

Tubing should be pulled through about an inch in each 2-litter cap

In the 20-ounce cap, one tubing line should be pulled through about an inch. Attach Check Valve to the other end of this line. And the 2nd tubing should be pulled far enough to reach the bottom of the bottle, so about 6 inches

Using Connectors
*Use as many, or as few, connectors needed to join all bottles into a single line. This single line is then jointed to the line that is pulled 6 inches into the 20-ounce cap

Adding Yeast Mix
Now, add a yeast mix of choice into each 2-liter bottle and fill 3/4 with warm water, not hot. There are many variations as to the suggested yeast ratio. I tried several options. Here's the thread with all the variations I tried when experimenting with different mixes/ingredients: DIY Plant CO2 Mix Experiment | Plant CO2 Forum | 92080

Take the 20-ounce bottle and fill 1/2 full with plain water. If wanted you can add some activated carbon to the bottom and continue to fill with water. I found no benefit in using activated carbon.

Set Up and Connect to Tank
*Place bottles in their designated location and connect system

*Take another tubing line and connect to the Check Valve and run this line into the aquarium.

*Use a diffuser of choice. The goal is to create the smallest bubble possible. The best diffuser I've found is either running the line into the intake of a canister filter or stuffing the end of the line with cotton. Standard airstones create too large of a bubble.

Notes
*Don't forget to set up an oxygen airline and run it overnight while the lights are off

*As most yeast mixes last about 2-weeks, I prefer to rotate when each bottle is refreshed. I take a permanent marker and write a number on each bottle. Then each weekend, change the next number. For example, on the 25G which has 2 generators, I change bottle #1 one weekend and bottle #2 the next. By rotating through the bottles you are attempting to stabilize the CO2 as much as possible.

*NEVER allow the mix to burn itself out. Otherwise, the highs and lows in CO2 production could lead to a BBA outbreak.

Please let me know if something is not clear.

 

Just wanted to add a little something from my experience, I used to silicon seal the tubes to the caps but I tried digging a hole with a scissor blade twisting back and forth just to where the tube couldn't fit, then I cut the end of the tube to a point poked it through, took pliers and pulled it through. Self seal and it actually worked beautifully. Before I would make the hole big enough for the tube to fit through easily then silicon but I'd always have a leak.

 

That's a great point Dang. If the hole is just large enough to force the tubing through it can be self-sealing.

 

Thanks Catsma! I'm sure many members will find this information very helpful.

Ken

 

Oh Thank you for the info! will keep it handy if I want to add CO2 to my tanks. lol

 

You are welcome. I couldn't find these instructions on this site already, and figured with all the questions it couldn't hurt.

 

@Dang it will be great if you help
@One 20-ounce bottle used as a bubble counter I didn't understand this part( I am a new bee and we cannot see these kind of things in our country a lot but I want my fish and plants to be happy) could you please explain if any pictures aided I would be great-full

 

You can use any smaller bottle. Do you have access to a single serving soda bottle? If not, how about a 1-liter bottle?

The purpose of this bottle is to see how many CO2 gas bubbles are produced before going into your tank. Plus it traps any of the yeast residue that may try to escape.

 

Yes I can get those bottles and I will try .
But I made a mistake yesterday due to curiosity I had already made the setup and running good without the bubble counter, as you said it will act as a filter I am worried now .
will the yeast do a lot of damage I will rectify it today night itself.

 

I'm not sure, honestly. I do know this bottle traps some yeast because the water gets cloudy. But it takes a few weeks to cloud up. My guess is that your filter would take care of the small amount that may make it into a tank. I have seen others not use a bubble counter.

 

I don't use any sort of bubble counter, I do have intentions of setting one up though. I just have a check valve since my bottles are under my tank in the stand.

 

I rectified it already and made another stupid mistake added 2 teaspoon sugar instead of 2 cups . And it went out of gas in one day itself and now after reading it thoroughly I have to rectify it also .But 2+2 4 cups of sugar I have to steal from my mom if she came to know she may throw me out. he he ..... And my family doesn't know too much about fish price and equipment price they leave me alone because they know I am obsessed with these fishes.
But I want to thank you guys for a nice thread when I was in a need

 

I would just throw more sugar in it maxamas

 

I rectified it already and made another stupid mistake added 2 teaspoon sugar instead of 2 cups . And it went out of gas in one day itself and now after reading it thoroughly I have to rectify it also .But 2+2 4 cups of sugar I have to steal from my mom if she came to know she may throw me out. he he ..... And my family doesn't know too much about fish price and equipment price they leave me alone because they know I am obsessed with these fishes.
But I want to thank you guys for a nice thread when I was in a need

I'm glad you found this information helpful. If we can add to it to make things easier, please let us know.

 

I would just throw more sugar in it maxamas

OK thank you . or shall I start it fresh?

I'm glad you found this information helpful. If we can add to it to make things easier, please let us know.

Here I am done thank you both for the help . I have a few more questions about my planted tank will start a separate thread if needed .{ All my plants rotted within a week except three or four variety still hanging and getting a good come back now after adding co2 }

 

Catsma knows a ton about it she's been more then patient with me. My plants are doing very well, some better then others.

 

OK thank you . or shall I start it fresh?

Here I am done thank you both for the help . I have a few more questions about my planted tank will start a separate thread if needed .{ All my plants rotted within a week except three or four variety still hanging and getting a good come back now after adding co2 }

A new thread would be more appropriate and would lead to more feedback. I will look for your thread and see if I can offer any suggestions.

Definitely leave your plants in the tank. They usually grow back after a melt so long as the roots are healthy and undisturbed.

 

Ive been using what is probably just a retail version of this DIY type system. I haven't seen it mentioned anywhere, but these things smell horrible. To the point where if I'm changing it when my girlfriend is here it almost makes her throw up.