Diy Co2

[TMRC Exotics]

I'm getting ready to setup a Diy Co2 setup on a 5.5 gallon tank, I'm not willing to go full blown tank injected co2 for this setup, so I'll likely be using diy for sometime. I would like to make a nice setup since it will be semi permanent, I'd just like to get some suggestions and/or links for diy co2 recipes and designs.
I'm looking at using a glass bottle/metal lid and brazing in some air tight outlets to attach tubing to, but if I can get a strong seal with plastic I may go with it. Any input is welcomed!

 

[Nils]

I am currently running DIY Co2 on my 5.5 gallon too. Super easy and it really does help the plants grow. I would personally not use a glass bottle just because if the line ever gets clogged and the Co2 can't escape, then it will explode and send glass shards everywhere. With a plastic bottle the most that damage that can be done is if the bottle leaks or the cap breaks or something. I use a plastic bottle and I doubt that any Co2 escapes.
What I did was I took a nail and a hammer and just poked a little hole in the top of the plastic lid. Then I pulled the airline tubing through the lid and made sure it was pretty tight. Next I took my hot glue and just sealed both sides of the cap to make it airtight. Works very well. Even my diffuser isn't one of those ceramic ones, it's just a cigarette filter. Works very well, makes a very fine bubble mist and I paid $2.50 for a pack of 100. I have to change it once a day.
My recipe is
1 Cup of sugar
1 tablespoon of baking soda (to stabilize pH)
3/4 a tablespoon of yeast
This recipe works perfectly for me and it lasts about a week. You could do more yeast and less sugar to produce more Co2 for a shorter period of time or more sugar and less yeast to produce not as much Co2 over a longer period of time. In the end it's very simple and a very cheap alternative to a pressurized system.

 

[TMRC Exotics]

I've put together a test rig with a plastic 2 liter bottle and a ball valve and tubing for now. Using 1 cup sugar and 1 tbsp yeast, 1 1/2 liters water.

 

[Nils]

That should work. Just make sure that you either have a way to release the Co2 after the lights go out as to not gas your fish or just take the Co2 out. Since plants can't absorb the Co2 in the water when they aren't doing photosynthesis there is a much higher concentration of it than if the lights were on. Just a heads up.

 

[Mebbid]

Check this out

 

[PerfectDepth]

I don't recommend trying to use yeast & sugar if you are using a valve to shut it off. Plastic bottles will also explode, not just glass ones. If it's airtight, a plastic bottle will blow up like a balloon and explode.. don't do it. I also don't recommend using those ceramic disc diffusers with DIY co2 for the same reason- they eventually get clogged which could be disastrous. I don't recommend letting a yeast & sugar generator build up any pressure at any time- the gas needs to be able to escape freely at all times with no chance of clogging to be totally safe.

The pressurized DIY co2 setups that use valves and gauges are meant for baking soda & citric acid generators, and are NOT meant to be used with yeast & sugar generators.

 

[PassengerTN]

According to myth busters, 2 liter bottles blow around 90psi. 60 psi pressure relief valve should give you peace of mind.

Jesse

 

[PassengerTN]

Or find a 3 way ball valve, where one direction would flow co2 towards the tank, and the other way would vent to atmosphere.

Jesse

 

[PerfectDepth]

For what it's worth, I run DIY co2 24/7 on my 20 gallon long with no issues. pH drop is 1.2 degrees from baseline pH at all times, even at night. I presume this is due to my internal reactor that uses a small powerhead. When the generators are both going strong, I notice more bubbles escaping the reactor, so I guess it keeps co2 concentration at an equilibrium, which is why the pH stays the same even at night when the plants are not uptaking co2. In other words, fewer bubbles escape the reactor when the demand is higher, and more bubbles escape when demand is lower. It actually seems to work exceptionally well for keeping co2 concentration steady.

I do have the powerhead on a timer, but it only shuts off for 1 minute in the middle of the night, just to clear the debris away from the powerhead's intake.

 

[TMRC Exotics]

Thanks everyone. The valve is just for temporary closing, I won't be blowing up any bottles, I have considered a few layouts of working proportionate adjusting in and honestly it looks like I'm going to have to. The fish are gasping at the top today so I've unhooked it for now. Without any stone on the tube its blowing 3 to 4 bubbles per second. The super simple two way valve with only one in the tank would be simplest, slap in a check valve and call it a day.

 

[TMRC Exotics]

So I did end up building my diy co2 system and have been running it a few months. I went with the simple two liter bottle running into a separator then into the tank. However I'm back to optimize the setup a bit and its led to some questions, any discussion is appreciated.

First question, why is the common suggestion a two liter bottle filled 3/4 with water? Is this amount of water necessary to facilitate the reaction, or could less water be used?

In the space my 2 liter bottle consumes I could place two one liter smartwater bottles, the idea being still using the same yeast/sugar ratios from the two liter in two smaller bottles to produce twice the co2. In terms of building pressure a larger bottle actually slows the initial building of pressure while providing no real advantage, two 1 liter bottles will theoretically double the same output provided the reduced water volume doesn't slow the reaction. Any thoughts?

 

[Fresh2o]

Space in the cabinet was an issue for me so I used 1 or 1.5 liter bottles: peroxide to remove any yeast.

I think the only disadvantage of smaller volumes is that the batches may not last as long as larger volume containers. I'm not sure if it is the exhaustion of sugar, shift in ph, or the toxicity of alcohol that slows down the yeast's production of CO2. Maybe a combination of the above.
One thing I used to do when making a new batch was to save a little bit of the precipitate/sludge at the bottom of the old batch and mix it with the new batch. I figured it contained quite a bit of actively growing yeast.
I used two containers and alternated each week with a new batch.


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[TMRC Exotics]

Space in the cabinet was an issue for me so I used 1 or 1.5 liter bottles: peroxide to remove any yeast.

I think the only disadvantage of smaller volumes is that the batches may not last as long as larger volume containers. I'm not sure if it is the exhaustion of sugar, shift in ph, or the toxicity of alcohol that slows down the yeast's production of CO2. Maybe a combination of the above.
One thing I used to do when making a new batch was to save a little bit of the precipitate/sludge at the bottom of the old batch and mix it with the new batch. I figured it contained quite a bit of actively growing yeast.
I used two containers and alternated each week with a new batch.


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Very good hypothesis on what's occurring in the smaller reactors. Definitely provides some things to look for. I think I'll reboot my current system and log the bps through my bubble counter, then make the switch and log the bps on the new system through the same timeframe.

 

[PoppaRyno]

Ive been mulling over the saving of some of my mulm to use in next batch. It seems to be the same thought behind baking & mother doughs... I wanna try some tinkering and am curious if i can get yeast system that i only have to feed.

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