Introduction
Vycor® is often used at the end of a reference electrode or a bridge tube to allow electrical,
ionic conductivity between the bulk of the solution and the internal filling solution, while
preventing large scale convective mixing of the solutions. Vycor, or "thirsty glass" is a porous
glass with a fairly low leak rate.
The Vycor frits, however, are not immortal!
To preserve their useful lifetime, they should be kept wet. If they are allowed to dry out,
solid crystals can clog the narrow pores and increase the electrical resistance. In extreme
cases, the Vycor can crack upon drying out.
When not in use, the reference electrode or bridge tube can be stored with the Vycor frit
immersed in distilled water. Diffusion through the Vycor is fairly slow, and the internal filling
solution will not be diluted, even upon a few weeks of storage.

An alternative is to replace the small plastic cap that was in place when the reference
electrode was shipped.