Can you mix two different bases?
Yes, it is perfectly possible to mix two different bases, provided they are both intended for vaping and of pharmaceutical grade. This mixing is actually a common trick to customize your PG/VG ratio or to avoid wasting the last bits of your bottles.
Just keep in mind that the final result will be the arithmetic average of your two components: mixing a 100% PG base with a 100% VG base will give you a perfect 50/50 balance. Make sure to shake the resulting mixture vigorously so that the densities harmonize correctly before adding your aromas. In short, it is a simple procedure that offers great freedom in personalizing your vape. The only golden rule remains the cleanliness of your containers.