tension measurements in sandy soils

[Bob Mittelstadt]

There has been some recent discussion on materials used to backfill
ceramic porous cup devices that are in contact with the surrounding
soil/water environment - bentonite being mentioned as one.

I am investigating the use of a connecting media between granular matrix
sensors (for measuring soil-water tension) and sandy soils.  Sandy soils
with a small percentage of fines are often not suitable for granular
matrix sensors due to, I believe, some difficulty in achieving
soil-water continuity between the porous media of the sensor and the
surrounding soil.

Is there a fine material that could be used as a slurry, having good
hydraulic conductivity, so that the sensor could communicate with the
surrounding soil without compromising the response time?

I would sure appreciate some suggestions.

Thank you,

Bob Mittelstadt
Othello, WA