Natural volcanic ash with beneficial properties for aquatic plant growth and long-term care of fishes and motile invertebrates requiring slightly-acidic, low-GH water conditions.Ideal for use as a substrate in shrimp biotope aquaria. Binds elements that contribute to hardness, lowering GH and resulting in a slight acidification of alkaline water to a pH of less than 7.Used as a primary substrate, forms the basis of a stable growth medium for rooted aquatic plants by:1. Permitting development of strong root systems.2. Encouraging nutrient-uptake through roots via increased interstitial water circulation (relative to higher-density substrata) and acidic pH environment.3. Allowing roots to remain sufficiently oxygenated to maintain plant health.