CaribSea Samurai Soil 9lbCaribSea Samurai Soil The ideal substrate for shrimp and planted aquaria This unique, uniformly graded material fits the pH and mineral requirements of the most sensitive freshwater fauna and flora, without the muddy texture and crumbling often seen with other brands. This complete substrate eco system is infused with mycorrhizal fungi for enhanced root development, and each package contains a dose of biologicals for a faster and more thorough cycle.