tubing used for CO2

[juggler]

I hear that some of the common air-line tubings we used for CO2 injection is not 100% "air-tight". Some gas can diffuse through the tubing wall and escape.

Is this true? How much loss are we talking about?
Any other alternative tubings we can use?

[anttz]

Are you referring to the soft tansparent type? When I just bought my Co2 sys, I was also told the same thing and was recommended the hard type (dark green in colour).

[tawauboy]

think the 'common air-line' tubing is referring to pvc types. losses through diffusion is >10%, if not wrong.
silicone tubing is an alternative. losses is something like ~5%.

[taz]

Or maybe you can use the industrial tube made from polyurethane. Can get from SMC Pneumatics (20m for like 20 bucks). 68610888

[CK Yeo]

Actually, if you are using a low pressure delievery device like CO2 reactor, it doesn't really matter what tubing you using. The amount you are losing is negligible as compared to the amount you are injecting in. 5% lost per feet of tubing.

Read this posted on APD

YOu will save more CO2 by controlling surface agitation and work on the efficiency of dissolving CO2 into water.

Only problem is maybe the stress from the CO2 and pressure, will weaken the tube over time and become brittle.

On the other hand, on the long term, you will probably save on CO2, changing brittle tubing or any CO2 leaks.

ck
P.s. Normal plastic joints for aquarium air pumps tend to leak under pressure. Dun use them.