If you use capacitance level meter in non-conductive media, you should use couple probe as a capacitor, the media as dielectric, the capacitance will be changed by the level. It just likes flat capcitor.
If you use capacitance level meter in conductive media, you have to use the insulated...
Capacitive probe level meter can be used in conductive media and non-conductive media both. just different type of probe. Of course, the temperature is importante, because the property of media will be changed along with tempertature.