5 parts perlite
4 parts bagged potting soil
1 part coarse sand
Pinch of rock dust
Top-dress the container soil with small river rock, gravel, aquarium stone, or a fine-grade roofing gravel to keep the crowns of the plants from rotting.
To increase acidity just slightly—something all succulents like—add 1 tablespoon white vinegar to 5 gallons water when watering.