Email thread:

From Jack Kelly <jkelly@ceh.ac.uk>
Hello Ankur,

I'm a technician with the Centre of Ecology and Hydrology in Lancaster, England.  We about to deploy these Vaisala CO2 sensors beneath our lake monitoring stations after some of our colleagues at our Edinburgh laboratory used them successfully in rivers.

The paper in question is Johnson et al. (2010) Ecohydrology 3, 68-78.

I believe that in the river experiment, the gas permeable tube used was an open-ended tube which had a bung sealed over its base.  The supplier also offers a tube which has one sealed end so we are aiming to use that for the lake monitoring.

The PTFE sleeve was ordered from;

International Polymer Engineering, 2445 W, Medtronic Way, Tempe, AZ 85281, US.
Its item number was 200-07-S-2 A1.  (which is the 25 cm length.)
Its description was 41171 Sealed High Porosity PTFE tubing.

The sealant came from Plastidip  (sales@plastidip.co.uk)

I hope the this is a help.  I'm afraid I have no practical experience of the material yet but the paper describes the original experiment in detail.

Ta  Jack