CANNA Clay Pebbles are baked clay pellets that form an ideal substrate for use by experienced growers. Thanks to their unique structure, CANNA Clay Pebbles offer the ideal basis for growers who want to control the application of nutrients and the humidity level of their plants throughout the entire process of cultivation in a simple way. CANNA Clay Pebbles are manufactured from special types of clay that have a low soluble salt content. Because of this, they are particularly suited for use in hydroponic cultivation systems.; We recommend using CANNA Aqua or VitaLink Max or VitaLink easy with this product.