Natural substrate for freshwater aquariums. Key features: • Optimal plant care through porous structure and nutrient storage function: Substrate for freshwater aquariums. • Strong plant growth, prevents algae: Effective stabilization of beneficial bacteria in the soil and ideal root growth thanks to the natural porous structure. Support for the filter. Crystal-clear water. • Ideal for fish, invertebrates, and plants: No unwanted pollutants are released into the water. Round-shaped granules gentle on the sensitive whiskers of bottom-dwelling creatures. • High storage capacity: The natural substrate absorbs excess nutrients and releases them when needed.