Mixing sand and humus with clay increases the stability of the resulting substrate and allows the animals to create burrows like in nature.Lucky Reptile Herp Pottery is a clay granulate. Its advantage over clay powder is that there is less dust during the mixing process. It can be mixed dry or dissolved in water. In the latter case the result is more homogenous. The more Herp Pottery you mix under the substrate the harder the result will be.Perfect for active and attractive terrarium sculpturing.