Tropica Nutrition Capsules supply your freshwater aquatic plants with all of the nutrients they require for healthy and sustained growth. They contain a proprietary blend of nitrogen, phosphor, iron, and other vital micro-nutrients. Nutrients are released slowly over time as plants need them. In addition to ensuring lush plant growth, Tropica Nutrition Capsules also promote the absorption of nutrients from the water, thereby reducing the risk of nuisance algae growth. Ideal for use with stem plants including Cryptocoryne, Echinodorus, Vallisneria, etc.