LECA Clay Pebbles Hydrokorrels Netherlands Import (40 Liter, approx. 19Kg)Netherlands Import Round & Evenly sized Size: 8 16mm As most commonly known as Hidroton or LECA (Lightweight expanded clay aggregate) or Hydrokorrels is also known as pH balanced expanded clay. These expanded shell pellets form a porous growing medium averaging 8 16 mm in diameter. Perfect for use with aquaponic, aeroponic and hydroponic gardens, including ebb and flow tables and systems that use grow cups to support plants. It is also used as