CO2 source
- Thread starter mattmartindrift
- Start date
So, what you're saying is, this would be about equivalent to a DIY CO2 setup with yeast and such?
I'm not understanding the cold argument; yes, CO2 solidfies around -78C, but, who says I'd inject it to my tank right as it sublimates? I'd let it at least sit at room temperature to equilibrate.
A pressure vessel isn't much of a concern as 2-4ccs of dry ice doesn't equate to much volume/pressure (in a reasonable container). That and I am an engineer by trade, so, my day-to-day DIY goes in production-scale chemical processes.
Now, all of these numbers are hypothetical, and I wouldn't do this without some actual number crunching and engineering.
However, yes, I do agree a pressurized CO2 tank is my best bet, but I don't want to spend that money, so I might abandon plants that require CO2.
If you are qualified and competent to handle this safely, then sure, why not. The worst that can happen is that you will waste a lot of dry ice without any positive result. At least you (and the rest of us) will know if it really works or not.
In fact, why not do it as a logged project. I don't know anything about dry ice or small pressure vessels and I think most of us here are in the same boat. If you know this stuff, then it will be interesting for the rest of us to see how you do it and what are the results.
In fact, why not do it as a logged project. I don't know anything about dry ice or small pressure vessels and I think most of us here are in the same boat. If you know this stuff, then it will be interesting for the rest of us to see how you do it and what are the results.
Que
I wish I was a fish I wish.
Why not save your breath and throw some pieces of dry ice into a garbage bag and bubble that into your tank with an airstone?
Q
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I'll run the numbers:
Density of dry ice: 1.5g/mL
So, 1 mL(cc) of dry ice is 1.5 g CO2
1.5g CO2 = 0.03409 mol CO2
Assuming it behaves ideally, you can use the ideal gas law and convert that into volume(being an engineer, I'll let you do that on your own):
now we have 830 cc of CO2 gas at room temperature out of one 1cc of dry ice. Expansion rate 830 to 1. That's just something to think about.
Moving on.
I can't find any information on the net about measuring the rate of sublimation for dry ice and I really don't feel like running any thermo calculations. However, I just set up a very rudimentary experiment in my lab. I've got ~10cc of dry ice sitting in a graduated cylinder. Started at 10 a.m. pacific. I'll let you know when it's all gone.
Density of dry ice: 1.5g/mL
So, 1 mL(cc) of dry ice is 1.5 g CO2
1.5g CO2 = 0.03409 mol CO2
Assuming it behaves ideally, you can use the ideal gas law and convert that into volume(being an engineer, I'll let you do that on your own):
now we have 830 cc of CO2 gas at room temperature out of one 1cc of dry ice. Expansion rate 830 to 1. That's just something to think about.
Moving on.
I can't find any information on the net about measuring the rate of sublimation for dry ice and I really don't feel like running any thermo calculations. However, I just set up a very rudimentary experiment in my lab. I've got ~10cc of dry ice sitting in a graduated cylinder. Started at 10 a.m. pacific. I'll let you know when it's all gone.
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I have two experiments going.
One started with about ~13 cc of dry ice. The volume measurement is a little erroneous because of the way this dry ice is produced, it may not be as compacted as others.
Therefore, I started another experiment. I started with 25g of dry ice(about 16.6 cc). In 15 minutes it's dropped from 25g to 17g at room temperature.
One started with about ~13 cc of dry ice. The volume measurement is a little erroneous because of the way this dry ice is produced, it may not be as compacted as others.
Therefore, I started another experiment. I started with 25g of dry ice(about 16.6 cc). In 15 minutes it's dropped from 25g to 17g at room temperature.
Less than an hour later, all dry ice has sublimed.
This was at room temperature and ambient pressure.
The way to slow down the release is to either increase pressure or decrease temperature.
You could use a 2 L bottle to increase pressure, just like people do with DIY yeast co2. The aquarium water would act as a pressure release. But, the question is, how much co2 would this put into the water....too much? too little? just right? That would require further experimentation.
But again, this is still cost prohibitive if you can't get dry ice for free.
As far as the temperature concern: The temperature of the co2 gas coming from the dry ice would be very cold...I believe we can agree on that. Also, in order to control the rate at which the dry ice sublimes, you have to insulate dry ice....I believe we can agree on that. So, when you insulate the dry ice, you are also insulating any gas that is around it. You'd have to remove the gas from you cold chamber and have it sit in another chamber to warm up before injecting it into your tank.
I'm not really arguing that it can't be done, just saying that would require a lot of space and a lot of effort. And, for anyone that has to purchase dry ice, it would cost more than DIY Yeast CO2 or Pressurized ever would.
Not to mention the fact that if you(people in general) think DIY CO2 is annoying because you have to change the mix every two weeks, you'd have to change the dry ice every day or so even if you put it in a cooler.
This was at room temperature and ambient pressure.
The way to slow down the release is to either increase pressure or decrease temperature.
You could use a 2 L bottle to increase pressure, just like people do with DIY yeast co2. The aquarium water would act as a pressure release. But, the question is, how much co2 would this put into the water....too much? too little? just right? That would require further experimentation.
But again, this is still cost prohibitive if you can't get dry ice for free.
As far as the temperature concern: The temperature of the co2 gas coming from the dry ice would be very cold...I believe we can agree on that. Also, in order to control the rate at which the dry ice sublimes, you have to insulate dry ice....I believe we can agree on that. So, when you insulate the dry ice, you are also insulating any gas that is around it. You'd have to remove the gas from you cold chamber and have it sit in another chamber to warm up before injecting it into your tank.
I'm not really arguing that it can't be done, just saying that would require a lot of space and a lot of effort. And, for anyone that has to purchase dry ice, it would cost more than DIY Yeast CO2 or Pressurized ever would.
Not to mention the fact that if you(people in general) think DIY CO2 is annoying because you have to change the mix every two weeks, you'd have to change the dry ice every day or so even if you put it in a cooler.
