caribsea eco-complete 20-pound planted aquarium, black. premium pack carib sea new formula for enhanced root development. why does eco-complete planted aquarium substrate outperform other products? for the same reason that hawaii, bali and costa rica are famous for lush, exuberant plant growth. the secret lies in rich basaltic volcanic soil which contains iron, calcium, magnesium, potassium, sulfur plus over 25 other elements to nourish your aquatic plants. eco-complete planted aquarium substrate is mineralogically and biologically complete, giving you luxuriant aquatic plant growth without nuisance algae. iron rich eco-complete eliminates the need for laterite. no artificial dyes, paints, or chemical coatings. eco-complete has highly porous spherical grains for optimum diffusion performance and contains live heterotrophic bacteria to rapidly convert fish waste into natural food for your aquatic plants. it establishes a natural biological balance which makes cycling a new aquarium faster and safer. directions: add eco-complete to empty aquarium, then add water, plants, start all filters and pumps. if adding to an existing tank, mix in a few pounds a day over a period of a week or more.