Does CO2 Get Through Tubing?

[Bronx19]

Hey guys. Im running a DIY CO2 on my tank and Im having probs. If I only place the last 3 inches of tubing in the tank the gas will bubble out. But if I run the tubing down to the bottom of the tank, the gas does not come out. It gets about half way down and stops.

Im sure there are no leaks anywhere, so Im wandering if the gas is leaching through the tubing and into the water?

Or is the gas dissolving into the water thats inside the tube?

[ninoboy]

It will take higher pressure for the bubble to start coming out if it's placed deeper in the tank. Did you just set it up? You have to wait at least half an hour to 2 hours until it built enough pressure in your DIY bottle.

Let it stay in the bottom for couple hours and then see what happen. If the gas/water level in the tube doesn't move lower, then you have a leak. When I had a leak, the gas level in the tube couldn't even push half way down the tank.

[Bronx19]

Ive had it up for days now. I dont know where the leak could be, I have a mound of silicone half an inch thick around the tubes/bottle.

[ninoboy]

I went thru this stage before couple months ago. It took me the whole night to figure out where the leak was (and another all nighter the following week). Well, assuming your mixture is ok, then:

What kind of bottle do you use? I tried different kind of bottles and end up using the old reliable coke 2L bottles. Some bottles are not air tight (the caps). It would pass all kind of test (submerge under water, etc) but couldn't hold enough pressure before it leaks.

Do you use any T-connector? I had a leak on the T before. This was the last place I could imagine leaking. I found out that some T conn. doesn't have smooth round ends. A little bump there could cause leak. I ended up seal all the connector with silicone (you can always peel it of next time).

Do you use a bubble counter or gas seperator? If you do, disconnect it first and run the tubing straight from the bottle to the tank.

Look for the leak step by step. You can run the tube straight from the bottle to the tank without any connector and check valves. If bubble comes out, then the leak must be somewhere in between. If this is ok, then you try using one of the connector. Add the device one by one until you find the leak. If the mixture is correct and has been there for days, it won't take long to start bubbling in your tank (20-30 minutes max).

[Bronx19]

Im using regular 2L coke bottles, with nothing but tubing into the tank.

There has to be a hole in the tubing (doubt it) or the lids arent holding.

[ninoboy]

How do you make the solution? How long did you let the outlet sit in the bottom of the tank before you decided that there is a leak? The coke bottle cap has the rubber insert. Don't throw that one away. It actually help to seal the bottle tighter (I have one without it also with no leak though).

[malkore]

you have some kind of micro leak. a pin hole somewhere. when the tubing is barely in the tank, the water pressure is reduced, adn the CO2 will go through the end of the tube. Add pressure, and it takes the quickest route to escape...being the small leak somewhere.

[djlen]

If you have the tube running directly from the bottle into the tank and a decent seal around the hole for the tubing, you should be getting gas into the tank. Especially with nothing on the end that is in the tank that would create back pressure. In the past, when I've run tubing from a 2-liter bottle through reactors that didn't cause any back pressure I've gotten away with not using any seal at all. I just made the hole in the bottle top very small and pushed the tubing into it and it worked fine.
I suggest you look at your mixture as it seems that it's not producing enough gas.

Len