Gold Label Custom 80/20 mix has been formulated to meet your horticultural needs. This mix is 80% Hydro Korrels and 20% coco fiber with added mycorrhizae. This formula contains extremely low levels of sodium and chloride for a coco substrate, ensuring a stable behavior throughout the use. Custom 80/20 is the tested and recommended growing medium for the Flo-n-Gro® system. 50 Liter.