# Advanced DIY CO2



## WarblyDoo

Hello All

I am new to this forum having just heard about it today and thought the best way to join the community would be to contribute something that has made my aquarium very successful. I looked through the existing forum and did not see many end to end descriptions on DIY CO2.

There are a couple of problems with the basic DIY CO2 that most people have, firstly it can be inconsistent, running for a couple of weeks then dying off to a trickle, not to mention the downtime due to de-pressurizing and the time it takes to get back up to pressure whenever you change the bottle which can cause a CO2 drop and subsequent PH swing. Secondly there is a lot of other waste gases that come from DIY CO2 which can clog diffusers. Finally there is a lot of additional wasted CO2, after a couple weeks the bubble rate goes down and we recharge it even though those little yeasts are still working hard and making gas for us, just not as much.

I have a system running on my aquarium which deals with a majority of these issues.

*Here's how I built it.*

Materials:
2 2 litre pop bottles
1 750 ml pop bottle
3 check valves
1 Air line T
Air line tubing. You can use as little or as much airline tubing as you want on each section. Just remember, too much will get tangled and too little will make it really hard to work with your reactor.


Into the cap of each 2 litre bottle use a drill bit to create a hole slightly smaller than the diameter of the tubing. Using a drill bit should create a nice round hole which makes for an airtight seal when you pull the tubing through.
Cut the airline tubing at an angle to make it easier to pull through the caps. It should be a tight fit, this ensures a nice seal. The tubing only needs to be pulled in about an inch.
Cut these tubes a few inches away from the caps and add a check valve onto each one with the outflow pointing away from the bottles.
Add another section of tubing and run the tubes from each cap into the T.
Drill two holes into the cap from the 750 ml pop bottle.
Pull air hose far enough through the 750 ml cap that it almost touches the bottom of the bottle.
Pull another air hose through the 750 ml cap but only so that it protrudes into the bottle about one inch
Attach the tube from step 6 to the outflow of the T in step 4
Attach a check valve to the tube from step 7 with the outflow pointed away from the bottle.
Attach an airline to the check valve in step 9 and run it into your tank.
Fill the 750 ml bottle about 1/3 to 1/2 full with water.
Charge the 2 litre CO2 generators with the recipe below

Notes:
Be sure to use pop bottles for your DIY system juice bottles and things like that are not designed to work under pressure and can fail. Having a CO2 generator burst (sometimes explosively) is a messy proposition.
Where the CO2 line in your tank goes will depend on your setup and equipment. If you have a fancy diffuser send it there. I have a cannister filter and a nano diffuser setup. I have screening on my canister intake to prevent my shrimp from getting sucked in and have flair it at the bottom so that it funnels CO2 bubbles into the filter to be dissolved, additionally the CO2 comes out of a nano diffuser to make the bubbles small and easy for the filter to pick up and deal with.

*CO2 Recipe*
1/2 tsp yeast
2 cups sugar
1 tsp baking soda

In a small bowl of luke warm water add a small amount (1 tbsp sugar) and sprinkle the yeast on top. It helps to allow the yeast to react in the air for a bit before we seal it in the bottle.
Into the 2 litre bottle place 2 cups of sugar and 1 tsp baking soda. Fill to just below where the bottle curves at the top with luke warm water. (You need to leave enough space so the bottle will be full to where the straight edges end and it curves towards the neck after you have added the yeast water.)
Shake the bottle to dissolve the sugar and baking soda (I find it useful to have an extra cap which I have not drilled a bunch of holes in for this step)
Pour the yeast water from the first step in. (I have heard different opinions on whether or not to shake the yeast into the mixture at this point. I have found that not shaking works well for me so I don't shake it)
Notes:
The water temperature is very important in this step. Too cold or too hot and you will kill the yeast. Luke warm water is best.
If you already do DIY CO2 you might have noticed I don't use much yeast in my recipe. Half as much yeast compared to most recipes allows the sugar to last longer, I let my generators run for 4 weeks switching out a different bottle every two weeks. By the end of 4 weeks they are pretty dead and I know I got the most out of them.

*Why did I go to all this trouble?*
I can recharge the bottles independently without de-pressurizing the system, the individual check valves on the two litres ensure that the rest of the system remains pressurised and the other two litre continues feeding CO2 to the aquarium.
Since I have twice the CO2 generators available I can use less yeast which allows the reactors to run longer.
I can alternate which bottles I recharge which allows me to let them run completely down since the other one picks up the load so I am not wasting as much sugar or yeast.
The 750 ml bottle acts as a gas seperator by letting the CO2 out and keeping the heavier materials in the water rather than in your tank or clogging up your diffuser.
The 750 ml bottle also acts and a bubble counter.
Finally the 750 ml bottle acts as a buffer. If a generator falls over the pressure will push the gunk inside into the 750 ml bottle before it goes into your tank buying you time to rectify the problem.

I have attached an image describing the system. Please be kind regarding my artistic abilities it was a quick mock up done in MSPaint.

Please let me know if you have any questions about how I built this or even advice on how to improve it. 

WarblyDoo


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## Tiwaz

Thanks, I see some changes coming to my setup.


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## sunshine_1965

I have tried the single 2L bottle version in the past. I also use the same ingredients. I will have to add a 2nd bottle to the system and give them a 2 week span this way I can mark the bottles to change on the 15th and 30th or 28th in Feb. I like your idea. Thanks for your contribution. I would imagine that a few people will give it a try. I have a few other CO2 recipes. Here they are for anyone that would like to try something different.

DIY CO2 


General rule is use multiple containers if you need a higher output, and offset their start dates to create a more stable flow of co2. be sure to check valve every bottle.

Standard yeast/sugar/water: (forget timeframe)
1 cup of sugar
warm water half way, shake it until dissolved
1/3 tsp yeast, let it stand for 5 min, then shake it.
fill bottle to 3" from top
add 1/4 tsp baking soda
the next day it should be producing bubbles.
*multiple bottle system with offset start dates is recommended with this batch.

Nyberg mix: (strong output, stable, less sugar and less yeast needed overall, 3-4 weeks)
1) 1 Cup of sugar, 2L of water, pour into bottle up to the start of the neck.
2) 1-2 tsp of protein mix or soya powder
3) 1 tbsp molasses
4) 1 tsp Baking Soda
first batch only: 5) 1/2 tsp of yeast
batches after this one do not need yeast most of the time, simply do steps 1-4, it should refresh unless you used bread yeast. if it doesn't refresh fully, add a 1/4 tsp of yeast and see how it goes from there.

Jello Mix: (long batch lengths, steady output, 2-4 months)
1) 2 packs of Jello, 2 cups of boiling water, Mix well, stir DONT SHAKE!
2) 1.5 cups of Sugar (more sugar lessons the life) mix well and dont shake it.
3) 1/2 tsp of baking soda (leave out if using champagne yeast)
4) 2 cups of cold water, mix well until everything is dissolved (don't shake....)
5) Refridgerate overnight (i recommend atleast 18 hours), you want jello, not a liquid jelly

6) once congealed, add one cup of room temperature water and 1/2 tsp yeast to the bottle. close up the cap, place on the counter and place the airline in a glass of water to confirm the yeast activated properly (bubbles come out)

if the yeast fails, dump out the water and do step 6 again. If the batch dies early, dump out half the the liquid and add more water and yeast to kick start it again.

Knox gelatine Mix: (higher output, less life than jello, approx 3 weeks)
Follow the directions on the knox packets
4 packets of knox
1 cup of water @ room temp , disolve the gelatine in it.
boil 2 cups of water with 2 cups of sugar
combine in an 8x8 pan and chill overnight
Cut into 1" cubes, place half the pan into a 2L bottle, let the cubes rise to room temp
fill bottle to 3" from the top, add 1/2 tsp yeast, 1/2 tsp of baking soda


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## WarblyDoo

I'll have to try some of those recipes. I like the idea of a long timeframe recipe. The less time I spend mixing CO2 the more time I can spend watching my fish. How is the output of the Jello mix compared to a regular sugar/water mix?


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## sunshine_1965

I have only done the top one so far. I will be trying the jello one soon.


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## Diztrbd1

sunshine_1965 said:


> I have a few other CO2 recipes. Here they are for anyone that would like to try something different.


 When you copy info from other sites, you should really give credit to the person who wrote it. Credit for that article in general, belongs to one of the members here. Was a great post by Neven. Here is the link to the full article: The Planted Tank Forum - View Single Post - Some advice on "trying" DIY CO2 request

Great post Warbly & welcome to the forum!


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## sunshine_1965

Diztrbd1 said:


> When you copy info from other sites, you should really give credit to the person who wrote it. Credit for that article in general, belongs to one of the members here. Was a great post by Neven. Here is the link to the full article: The Planted Tank Forum - View Single Post - Some advice on "trying" DIY CO2 request
> 
> Great post Warbly & welcome to the forum!


I copied it just the way it was sent to me so credit goes to whomever sent it to me a couple months ago. It was not Neven. Thanks.


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## Diztrbd1

either way it's a good article, now ya have the link for the full write up :bigsmile: Neven's like the diy co2 guru lol


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## Tiwaz

Just added the second bottle to my setup. Everything is bubbling away nicely.
Thanks for this.


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## neven

the original post is actually from this site. Here to be exact:
http://www.bcaquaria.com/forum/plants-algae-ferts-ei-co2-lighting-13/basic-guide-carbon-dioxide-81/

The only credit i care about is that the information came from BCA, not me specifically. I wouldn't call me a guru, i compiled the different methods i've tried (save for the knox method, thats rex griggs recipe) and tried to compare them to each other rather than "this one is better". The goal was to save people the need to search, so in one thread, you have Pressurized, liquid based and DIY methods for all the same topic. well that reason and the fact i was bored and noticed the thread had no replies, sitting there, just nagging me to add on 

On a side note, im on pressurized now. My 29 Gallon did better on Jello co2 than pressurized, but my 9.8 gallon tanks couldn't fit the reactor where they were, so i keep everything on the pressurized rather than sell it.


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## blurry

Would this DIY system work with a 20 gallon long?


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## neven

i've heard of people using even the basic formula with multiple bottles on even a 50 gallon. It works if diffusion is fine, and you have no issues being religious about maintaining the bottle change out routine. I would ALWAYs use more than one reactor (bottle) to maintain co2 levels much more efficiently, even on smaller tanks. UNless you go for jello co2, then a good batch lasts atleast 3 months of solid high output


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## blurry

For the jello one, what kind of bottle would you use? And one or two Bottles.


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## neven

for two liter bottles, i would say 1 for every 10 gallons. If you use a container that is more square and long, say like a canola oil jug or a gas jerry can, the exposed surface area is much greater, so i would say 1L per 10 gallons (ie canola jug 3L is what i used on my 29 Gallon). The reason jello lasts a lot longer is because as the yeast consumes the gelatin and sugar, it releases water with it. So if the mix is balanced, then it stays diluted not allowing the alcohol % too high to kill of the yeast


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## WarblyDoo

The jerry can is a really interesting idea I hadn't even thought of that. You never had any problems with the canola oil jug? When I was researching how to build my setup I read on several sites that you should never use bottles like that since they are not designed to act as pressure vessels. Jerry cans likely wouldn't have that problem since they are designed to hold the pressure that gasoline exerts.


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