How can I prevent the water in my inclinometer from freezing?

To prevent the water from freezing we recommend filling the casing with a water + propylene glycol solution. Propylene glycol is a non-toxic antifreeze fluid. Although this solution should be harmless, always wash off the probe and cable after use.

Here is a table showing the freezing point for various solutions. The table is provided by engineeringtoolbox.com.