DIY Plant CO2 Mix Experiment

Instructions for setting up DIY CO2 System

As I have been experimenting with different mixes to add to my DIY CO2 bottles, I thought I'd start this thread to document my findings.

Feel free to add your personal triumphs and failures too.....

Conversion Chart for those outside the US:
1 cup = 8 fluid ounces = 236.59 ml
2 cups = 16 fluid ounces = 473.18 ml

1/4 tsp = 1.23 ml
1/2 tsp = 2.47 ml
1 tsp = 4.93 ml

Option #1
*1/4 tsp yeast
*1/4 tsp baking soda
*2 cups sugar

When I begun using DIY CO2 about 9 months ago, this was the primary recipe I found on the net. This mix lasted 10-14 days and seemed to be decent at producing a steady stream of CO2. But it was also my first mix option, so what did I know?

Option #2
*1/2 tsp yeast
*2 cups sugar

Increased yeast and no baking soda. This mix actually worked better with my tap water. This mix would last 2-3 weeks.

Option #3
*1 tsp yeast
*2 cups sugar

This option worked better for me during the winter months and would last up to 4 weeks. Overnight my house would cool down to 65F and the gas would come to a standstill, but once the heater warmed the air up, I would give each bottle a good shake and get things moving again.

What I like about this is that the CO2 production pretty much became nil overnight; but the morning shake would get things moving again.

Option #4
*1/2 tsp yeast
*1 cup sugar

I did not have great success with this mix as it would burn out quickly and needed replacing every 7-10 days.

Option #5
*1/2 tsp yeast
*2 cups sugar
*Single shrimp pellet or fish food flake

Now, I thought this was crazy. Why add fish food to the CO2 generator? But, what I found was that the mix would last 3-4 weeks. By adding the fish food the mix appeared to last a week longer!

I haven't quite worked it out yet, but I believe that the ammonia produced by decomposition may be a factor.

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Now, I have also been reading about using Knox Gelatin to make a solid sugar/protein block for the yeast to feed off of. Very interesting, but a lot more work. I plan on trying this one day.

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And, earlier this month, I read an article about making wine from a can of frozen grape juice. They took a 1 gallon jug and instructed you to pick up a check valve and airline tubing from an aquarium store. And, provided step by step instructions on how to add the airline into the bottle cap, use hot glue to seal and add the check valve to release the CO2 and not allow air back into the jug. And, in a month you would have wine.

This article got me to thinking about how similar it was to our DIY CO2 generators.

Once the weather warms up, I think I might try this. Making wine in my generator and dosing CO2 into my aquarium! How much better can it get?

Oh, I forgot to mention, currently I am using 1/4 tsp yeast, 2 cups sugar and in 4 bottles I also added 1/4 tsp baking soda. These generator bottles are sitting on top of a heating pad that is left on day and night.

This has been the case for a week now. And, so far so good. The CO2 continues to produce overnight and appears to be more steady. Time will tell if the mix wil burn out in another week or not.

The reason I have 4 bottles with baking soda and 4 without is because I wanted to determine, yet again, if baking soda made any difference.

My tap water tests out at:
6.8 pH
0 NH4
0 NO2
0 NO3
2 PPM PO4
4 dGH
10 dKH

 

It has been 1 week and the non-baking soda bottles have almost stopped CO2 production while the bottles with baking soda are still going, but slowing down.

I forgot to pick up the gelatin when I was at the store to try the gel mix to have something to compare to. So, in the morning, I will be mixing up 1 tsp yeast, 2 cups sugar and 1/4 tsp baking soda to see how long this mix will last.

Changed out #1 set of bottles and added 1 tsp yeast, 2 cups sugar, 1/4 tsp baking soda and 1/4 tsp corn starch. Reading about alcoholic drink manufacturing and the need for a grain starch gave me this idea.

Never tried using corn starch before. See what happens.

 

Is there a link to the article for making the wine? I might want to try that.

 

Do a search for frozen grape juice wine and you'll get many hits. Here's one of the how tos I was looking at the other day......

If you make wine and gas off the CO2 into your aquarium, please share your experience!

 

Very interesting. Thanks for sharing! I have often wondered which formula works best. I p/u geletin and yeast to try that formula. I'll be eager to see how it works out for you. I still want to try a plant only tank w/ CO2. Keep posting you results!

 

Please post your results psalm. It is something that I am interested in trying as well.

It has only been a couple of days since I refreshed one set of bottles and added cornstarch, and I cannot believe how much CO2 is being generated, and how steady the output is. I believe I will use the same mix with each set that gets refreshed over the next couple of weeks. I just hope this mix doesn't start strong and suddenly burn out. Time will tell.

The #1 set of bottles are still going strong after a week. Changed the #2 set of bottles and used 1 tsp yeast, 1/4 tsp baking soda, 1/2 tsp corn starch, 2 cups of sugar. Seeing if extra corn starch will keep the yeast going longer or not.

Has anyone considered using a small sponge filter with CO2? I wonder if it could work? I may have to pick one up and try it.

FYI - the new bottles I set up this afternoon are already producing 1+ bubbles per second. It sure didn't take it long to start producing. As my doors were open most of the afternoon and our high was in the mid 50s, I think the corn starch is helping to get it started faster....and in lower temps.

 

is this mixes for 1 liter bottles?

 

For a 2-liter bottle. If you are using 1-liter, then cut in half.

 

hI so I got my CO2 bottles ready , which mix should I use ? thanks

 

Did you ever try the mix w/ geletin? Do you think CO2 w/out a tank cover would benefit plants or not? Thanks. Seems the cornstarch & baking soda really help. Good to know.

 

No, I have not yet tried the gelitin. Too much going on at work.

For now, I've been sticking with the corn starch and baking soda. The mix starts faster and seems to last 2 - 3 weeks.

I still plan on trying the gelitin. Will post results as soon as I do.

 

hI catsma should I try the mix#3 you said that it came to a standstill when it cooled down , so what if I put it in a cooler box with a cold pack at night so it will bring the temperature down a bit then it will come to a standstill right? and in the morning I take it out of the cooler box and give it a shake to get it going. , and the plants don't need it at night right ?

 

It has been my experience that an airstone at night was sufficient. Attempts to force a slow down might make it harder to warm up the yeast mix to get production back in full swing.

If you decide to try this, please post your results. One concern would be too great a fluctuation of CO2, which can lead to a lack of plant growth and an over abundance of algae.

 

oh id rather not try that then can't I just take the pipe out of the tank at night ? and what should I put at the end of the pipe an arirstone?

 

I am just starting to use CO2 so I am interested in your results.

 

oh id rather not try that then can't I just take the pipe out of the tank at night ? and what should I put at the end of the pipe an arirstone?

I am using an airstone to add CO2 to my tank. I have also tried placing the end of the CO2 line in the intake tube to my filter to help diffuse it better. But, I kept forgetting to check on it and my CO2 production would completely stop before I would notice. This lead to a horrible algae outbreak. So, now it's an airstone. I have also read that you can shove a small piece of chopstick into the tubing to diffuse the CO2, but that it would need replacing every week or two to avoid plugging up.

I am just starting to use CO2 so I am interested in your results.

Please share your experiences. I started this thread because I was trying out all the various recipes I found on the internet. And, not knowing which worked better or which lasted longer, I wanted to share my experiences.

 

I bought a Natural Plant System by Hagen. I made my first batch last weekend. I am getting 6 bubbles per minute on the plastic ladder that came with it. The container is smaller than a 2 liter. I make get more on my next batch. I may also make a larger container to use too.

 

I just used the option #3 with two 2l bottles and I'm getting about a bubble a second maybe a bubble and a half a second. I set I up yesterday night , do you think the bubble count will go up?

 

It might, but probably not more than 2 bubbles per second. This should be fine for your tank. Just watch it for a couple of days to know.

Since you started both bottles at the same time, you are going to have a sudden drop in production. Once the CO2 production starts to slow down, you will want to start a new mix in one of the bottles so they are staggered to keep production as steady as possible.

 

oh ok thanks how long should this last?

 

I would guess around 4-5 days as this mix is usually done around 7-10 days.

 

wow that's not long at all , but it says for you it lasted around 3-4 weeks?

 

Oops. I've tried so many different mixes, that I am losing track of what they did. You are correct in that this mix lasted about 3 weeks. So, that would mean that you would want to change one bottle in 10-14 days. Then, one bottle every 3 weeks from there. You never want to let the mix completely stop production.

 

oh thanks so much . I can't wait for my plants to grow

 

This morning I was getting 10 bubbles per minute. This weekend I will work on making a second bottle to use. I think the current mix will last a few weeks. I will also be considering more plants.

 

I was thinking of finding a gallon container. I think a restaurant size plastic jar for mayo or salad dressings would be good. Has anyone ever tried a container that size.

 

I have not, but other use large, even 5 gallon containers, for Co2.

 

Now that all my CO2 generator bottles are holding the mix with the corn starch, I am finding that I am getting 2-3 bubbles per second and am having to watch my tank closely as I am on the verge of overdosing my tank. Plants are loving it....fish are not impressed.

 

I got a one gallon plastic jug from a local restaurant. I hope to get the tubing and install it this weekend.

 

I am going to hook up the 2 co2 containers to a gang air line valve and feed it to the plastic ladder.

 

Good luck Mike. Hope it works out for you.

 

I put 2 tsp yeast, 4 cups sugar, 1/2 tsp baking soda and 1/2 tsp corn starch in my gallon container. I had problems getting bubbles. I thought it was leaks at the container, but traced it to my gang valve. I paid extra for a metal one that I thought would be better. I switched to a plastic one. It's solid plastic with needle valves and rubber gaskets.

I do have problems with the bubbles coming in spurts and not a continuous stream of bubbles. Does anyone have any ideas why they are not a steady stream?

Now I have to figure out when my little bottle with be done. I will either get another gallon jug or use the little one while I refill the big one.

 

For me, I usually get 2 bubbles per second; and occasionally 3....and rarely 4-5 bubbles. Does this sound similar to what you're getting?

From what I understand, it all depends on how much CO2 the yeast is creating as well as how quickly it is released from the water in the jug.

It will be interesting to see how long your mix lasts.

Hope this helps.

 

I get a big surge of bubbles. So many that some come out of the ladder. Then I don't get any for a second or 2. Then I get a steady stream of bubbles for several seconds until the next surge of bubbles.

I am working 2 jobs now so I don't get much time to watch. I have the next 2days off from one of the jobs. I have other things to do, but I hope to get some time to spend on my tanks.

 

It may be entirely possible this is "normal" as you are using a much larger jug than I am. Also, it can take up to 2 days to reach full CO2 production. I'd imagine that once the pressure is built up in the bottle that things would become a bit more steady.

Just keep an eye on it to see if it changes.

Do you have a drop checker or other means to estimate how much CO2 is dissolved in your tank?

 

No, I don't have anything to measure the CO2. I just started lloking at methods to measure it.

 

Here's one method that only requires a few pH tests.....

Remove a couple cups of tank water to a container and aerate it. Test 24 hours later as all CO2 should have been released by this point. We'll call the your tank's natural pH.

While aerating your water sample, test the pH just before lights on, at the half way point and just after lights out. This will give you the pH range as more CO2 is absorbed into the tank. Let's call this sample pH.

Then, do a little math as follows:

(Tank's Natural pH - Sample pH) * 30

It takes 30PPM CO2 to lower pH 1 degree. For example, my tank has a Natural pH of 7.0; and my Sample pH drops to 6.2. So the math would be (7.0 - 6.2) * 30 = 24PPM CO2.

This is only a rough estimate, but will at least give you an idea how much CO2 is getting into your tank.

 

I have a few questions:

Which one of these methods did you find to be easier on the budget, easier to manage, and last the longest (all *relatively* at the same time )?

And do you recommend an air stone, just plain open tubing, or something else?

Last one! How do you reduce the number of bubbles that comes out? Just by tying the tubing, like when you are drip acclimating?

 

The best diffuser is actually a small piece cut from a cotton makeup pad. Stuff it into the end of the CO2 tubing. The tighter the better. It will create very fine bubbles to improve diffusion. I use the cotton on my O2 tubes as well, just don't pack it so tightly or it puts too much pressure on the air pump.

Do not attempt to stop the CO2 output from a DIY generator. Otherwise, the bottle will explode. This is why it is important to add an O2 light during lights out.

Hope that helps.

 

I still don't get how to slow the amount of bubbles that comes out.

Also, could I just use, like, a cotton ball, to the same effect?