Whats the biggest DIY CO2 bottle you can make? - Page 2 - DIY Aquarium Projects

Elrodg · 10-06-2011, 03:42 PM

The trick is to reduce your output area with each bottle. And a gas separation tank made from a 20oz bottle. This all bleeds into the pressure tank. A needle valve setup will add extra pressure by restricting flow but you have to have a tank of sorts that can handle more pressure. I use a strong sugar mix with a half tsp yeast in the first bottle and reducing mix as you go down the chain.

boognishmofo · 10-09-2011, 06:45 PM

I was trying if possible reduce the amount of 2 litre bottles I use. Thought maybe if big enough I could use one container.

Elrodg · 10-10-2011, 06:34 AM

Well I made a four gallon one out of an old water jug. (plastic or glass works). Hard part is finding a stopper. But if you look for chemistry supply sites you can find one.

boognishmofo · 10-12-2011, 09:33 PM

Quote:

Originally Posted by Elrodg

Well I made a four gallon one out of an old water jug. (plastic or glass works). Hard part is finding a stopper. But if you look for chemistry supply sites you can find one.

How long does it last?
What size tank?
What is your ppm?
How large of a recipe?

If from what I understand correctly, the larger volume of water used the longer the yeast can stay alive. Is this right? You could add more sugar half way though the phase to feed it again.
I was looking at my dogs water jug, the same I believe your talking about.

Lizid · 10-12-2011, 11:00 PM

Hmmm guy this is a very interesting I have just setup a DIY system so I am also very interested in what's being said, but my next question I need to ask is, at what point doest it just not make sense to run DIY?

I will keep following this thread as I am really thinking about the same problems...

tokyo · 10-12-2011, 11:40 PM

To prolong the production there are a few things I would try:

1. Decrease the rate of alcohol/CO2 production. There are three main ways to do this; reduce temperature, reduce the amount of yeast initially added, reduce the amount of oxygen in the mixture(oxygen = reproduction).

With a reduced rate of production you would need to increase the volume of the mixture, keeping the same ratio(water:sugar:yeast) in order to maintain the amount of CO2 produced.

2. Use a yeast with a higher alcohol tolerance. It is the alcohol that builds up in the mixture which kills the yeast. So a yeast with a higher alcohol tolerance would allow more alcohol to build up before dying. Regular bread yeast has an alcohol tolerance of around 10-12%(if I remember correctly). There are specialty brewing yeasts that have alcohol tolerances as high as the mid 20s, possibly higher. The downside is that they tend to be a bit pricier than the bread yeast that you can pick up at any grocery store.

3. Slow release food. Basically, the gelatin method, as has been mentioned previously, allows sugars to slowly be made available to the yeast rather than having an unlimited amount available from the start. This another method for decreasing the rate of production. I'm not sure why I separated it from the others.

I think if you used all or most of these methods you could extend the life your DIY CO2 batches considerably. But it would most likely take some experimentation.

.02

SlyDer · 10-13-2011, 02:14 PM

Several years ago I used a 3 gallon jug on my 55 gal planted. The result was increased co2 output (what i needed at the time).However, I never could get it to last more than 2 weeks before the production got so low that it was no longer worth it.

D9Vin · 10-13-2011, 02:39 PM

I have been following this thread for a while, so I suppose it's time to throw my 2 cents in the bucket. I think, and this is total theory, the reason you can only get the mix to last around two weeks, and the reason the gelatin method works, is you must consider yeast is alive and reproducing. If there is plenty of food, there will inevitably be plenty of yeast, regardless to the initial yeast amount. If you made a 55 gallon drum diy unit, and kept the same proportionate amount of sugar, but only put in a teaspoon of yeast, it may take longer to really get going, but eventually as the yeast population grows, you are just going to produce an insane amount of co2 over maybe a 2 1/2 week period. I am guessing the gelatin restricts the movement a bit and thereby the access to the sugar.

tokyo · 10-13-2011, 02:46 PM

Quote:

Originally Posted by D9Vin

...yeast is alive and reproducing. If there is plenty of food, there will inevitably be plenty of yeast, regardless to the initial yeast amount. If you made a 55 gallon drum diy unit, and kept the same proportionate amount of sugar, but only put in a teaspoon of yeast, it may take longer to really get going, but eventually as the yeast population grows, you are just going to produce an insane amount of co2 over maybe a 2 1/2 week period.

The yeast only reproduces while oxygen is present. This is why limiting the oxygen as well as the initial amount of yeast should work to slow down alcohol production and therefore extend the life of the yeast.

D9Vin · 10-14-2011, 06:13 AM

How would you limit the oxygen? Is it as simple as filling the bottle up more?