I use the Hagen CO2 Tubing and standard clear vinyl tubing.

Each line is about 4 feet long. I haven't noticed any brittleness or stiffness. Probably will replace tubing with the same stuff when the next refill comes along in a couple of months.

-John N.

 

i use 1/4" polypropylene tubing that is used for situations like reverse osmosis etc. regular airline tubing has about a 10% co2 loss while co2 tubing has 1% or less loss...the water tubing is pretty thick and dense...so, i am going to just guesstimate that the water line is somewhere inbetween.

at $2 (or so) for 20 feet...it is a heck of a lot cheaper than co2 tubing that is about 99 cents a foot (give or take)..

 

I use Norprene (black) tubing on my tanks. While it is more expensive than other types of tubing, it is about he same price as other CO2 tubing. It is also highly flexable and I have yet to see it kink in any of my applications.

Norprene tubing can be found at US Plastics for a decent price and most online places offer discounts for purchasing in bulk. If they don't advertie it, ask! Purchasing in bulk is a good idea for those involved in plant clubs. You save on shipping and the per unit price by combining all orders into one! SWOAPE coordinates group orders (Greg Watson, US Plastics, Dry Goods, etc) whenever someone needs something. A club forum is a good place to "advertise" a group order.

Sorry for getting off topic a bit

 

I personally recommend FEP for semi-rigid, or vinyl for flexible. Vinyl actually as a better permeability rating than Norprene.

http://www.coleparmer.com/techinfo/techinfo.asp?openlist=D,E,C&htmlfile=SelectingTubing.htm

 

I use 1/8" Tygon. It's thick walled but still flexible. It feels soft to the hand. It's permeability rating is good also.

 

Everytime we have this sort of CO2 tubing discussion, it always gets into permeability.

I think I said this before, doesn't that mean if I use for example silicone (supposely highly permeable, and bad for CO2 applications) that if I stuck the whole line under water, from regulator to diffuser that I would see bubbles coming of the line?

I just tested it with my airline tubing and hagen tubing using a small 1lb cylinder, a filled water bottle with the tubing going through the top cap and out the bottom from my azoo regulator, and the rest of the tubing in the sink. So all tubing was submersed in water. Result no bubbles except from the glass diffuser.

Granted I only ran it for about 5 minutes under 1-2 bubbles per second. But, basically my point is, all tubing needs to replaced at least once a year, no matter how CO2 proof it. I think for our purposes the tubing really doesn't matter.

But I'm curious to see what other people are using as well...keep them coming.

-John N.

 

John, by 'permeability', I think they are referring to it on a molecular/diffusion type basis. You won't see gas bubbles forming under water. I would venture a guess that if you left a highly permeable line full of CO2 in water over a period of time that the water pH would drop due to the permeability, but it isn't something you will see quickly.

 

Everytime we have this sort of CO2 tubing discussion, it always gets into permeability.

It sure does. The only "real life" difference I have noticed between Norprene and regular air line hose is that the air line hose section that is under water becomes brittle after 6 months or so. The Norprene is soft and flexible and remains that way, even under water.

Sometimes I wonder, especially since CO2 is so cheap, if we should really bother with CO2 tubing at all. I mean, how much CO2 do we really save by using CO2 specific tubing over regular, cheap, airline? IS it even worht the cost of the tubing itself?