Hydroton is the trade name for “lightweight expanded clay aggregate” or LECA. Simply put, small clay balls are heated in a rotary kiln to about 1200° C of expanding and form a hard clay particle about the size of a marble.
Advantages:
Reusable, sterile because of high temperatures during production, and has a high air-porosity potential.
Disadvantages:
The product typically contains dust that must be washed prior to use. Hydroton is practically inert, having almost no cation exchange capacity.