Dry Ice for CO2?

[jerman]

Can you use dry ice for CO2. Has it ever been done or tried. I havnt though up a delivery system yet but I think there has to be some way to harness that concentrated co2.
I'm thinking of using a 2 liter bottle and drop in a dry ice chip every 2 days. While finding a way to create a steady stream of co2, instead of a 5 min concentrated dosing
Is dry ice in any way Bad co2?
Thanks

 

[Wizzard~Of~Ozz]

Dry ice is far too risky. the extreme temperature in it's native state may break down the plastic your thinking of housing it in. Also you have no way of regulating the outgas..

 

[Skyrmir]

What you end up with is in order to do it safely, you either have to have a container that will vent the excess pressure (and waste a LOT of the gas) or a tank that can hold the pressure, wich would require a regulator to handle the pressure. At wich point, refilling a co2 tank is cheaper than figuring out how to safely put a useful amount of dry ice into one.

Either way, an actual co2 tank with regulator ends up being the better solution.

 

[jerman]

dry ice

Ok thanks for the feedback. Yeah I was thinkin of a way to get more co2 without dropping $150 on a pressurized tank setup. I know I can do the setup for between $100-150 but its the fact that its ANOTHER 150, and before I know it it will be another $150 for something else and so on

 

[nitrous]

u can do a diy setup for co2 thats pretty cheap

 

[7Enigma]

Ha, funny I see this thread. I have been thinking about the dry ice route for a couple of days now, and actually added it in a recent post. My idea was to put a very small piece (the size of a small stone) into a place where the fish cannot get to in the tank so that it has a much longer contact time with the water than if it were to just bubble at the surface. Would also make for some really cool pictures with the "fog" at the surface of the water. Regulation would obviously be impossible, but if you need a short term fix, I'm pretty sure it would work.

justin

 

[Wizzard~Of~Ozz]

or cryogenically preserve your fish for eternity

 

[MarcoDaVinci]

The chemist point of view : Dry ice contains a little oil, it comes from the compressors used to make it. I beleive it is safe for your tank because the oil will not evaporate, it will just make your device dirty after a while. DO NOT put peaces of dry ice in the tank, this stuff is not very clean.

The engineer point of view : COOL ! You will have to put your dry ice in an insulated container in oirder to slow down the evaporating process and make it last for days. DO NOT use a glass dewar, it may explode. Plastic may be hazardous too for it becomes brittle at -78.5 Celsius. How about a good old stainless steel coffee thermos ?

The cheapest pressure releif device : fill a 6 ft plastic tube (the 1/8 inch type for air bubbles)with water, let it go down and back up, in a U-shape, and connect one end to your device. In case of excessive pressure, the pressure will push the water out. That's it !

 

[malkore]

I have played with dry ice many, many times over the years (dad used to get Omaha steaks, which are shipped in like, 3lbs of dry ice...a kids dream!)

little chips of dry ice last about 3 mins in water, and once they're gone, they're gone.
They also make that water EXTREMELY cold. You'd have to have some kind of robot dropping dry ice chips in a separate container, then run that into a diffuser, and reheat the water a little extra.

Sadly, dry ice sublimates so quickly, that you'd be spending $5 a day on dry ice blocks, and would need them delivered every day or two.

 

[greenmaji]

Well.. if you have a HAVC refigerant recovery unit, a sutable container and a gas recovery canister you could give recompressing the gas a shot.

the "sutable container" would be an experiment in DIY skills, a large flaired outlet that you could use to drop the pellets in, a PSI gauge and a service port, and for greef sake braze it up and preasure test it with NO2 underwater for 24hrs 200PSI should be fine

IMHO unless you have acess to the tools this project could get pretty expensive fast..

 

[hashbaz]

I think yeast would be easier and cheaper but not as fun, and this way may actually work:

Get a large trash bag, suck all the air out and drop in your dry ice. (If the dry ice damages the bag, wrap the ice in paper first). Use a rubber band to tie the opening of the trash bag around an airline tube.

Run the tube into the aquarium and into a bell diffusor. A large enough bell will have enough surface area to dissolve the CO2 fast enough and will be able to hold enough CO2 for a day or so.

When your bell needs CO2, open the door to your stand, and give the bag a squeeze.

***edit*** Don't forget to put in a one-way valve. It just occured to me that if the outlet of the hose is in the water (and not the co2 in the bell) then it is very, very likely that after you stop squeezing, water will flow back into the airline with enough momentum to go up and over the side of your tank and into your garbage bag and continue siphoning until you have a huge problem.

 

[czcz]

Very clever.

 

[clengman]

I came across this old post a little while ago because I was brainstorming ways to inject a little CO2 into my planted tank at work. I work in a lab and always have dry ice around.



I think I've worked out a pretty safe and effective way to use dry ice for a diy CO2 system. There is significant potential for dangerous explosions, though, so try it at your own risk.


The third photo is all the parts and pieces. I have an insulated container to keep my vessel full of dry ice cold, two adjustable valves, one to control flow to the tank, one as a pressure release, a bubble counter, and an airstone in the tank.


The second photo is inside the cooler. I have a 500 ml PTFE bottle with a tight-fitting lid that I fill about half way with dry ice. I run a piece of tygon tubing through a hole in the lid and out through another hole in the lid of the cooler.


The first picture is the plumbing that allows the system to be fairly safe (I think). I have a y fitting with two adjustable valves, the valve running to the bubble counter I leave fully open unless the volume of dry ice is so low that I am not getting enough pressure to push a bubble through to the airstone. I use the second valve to regulate the pressure in the 500 ml bottle and thus control the flow.



Keeping the pressure vessel inside the cooler keeps everything cold and slows the sublimation of the dry ice to a manageable rate.


It requires a little fiddling after I first fill the bottle with dry ice, but once everything is loaded and the temp inside the cooler is equilibrated, and the valves are adjusted, I get a fairly steady input of CO2 to the tank. And since both valves are always open, and bleeding off pressure from the dry ice vessel, there's little chance of a rupture (and if pressure did start to build, the tubing entering the y fitting would be the first connection to fail at a not dangerous amount of pressure.)



It's not a set it and forget it system, but it works ok for something I essentially cobbled together for free from spare parts around the lab. I'm happy with it for now!