Activated Charcoal also known as Activated Carbon
Activated Charcoal serves as a filtration layer.
This layer is built above the the drainage layer on top of the seperation layer.
It helps to purify the water that runs off the plants, any decay, through the soil and into the drainage layer. In our eyes it is an absolute must to keep your terrarium healthy.
Lay your terrarium activated charcoal layer at least 1 to 2 cm deep.