Kent Marine Iron and Magnesuim Supplement, 16 oz. Kent Marine Super Chelated Iron Supplement supplies needed iron, manganese, potassium and minor trace minerals for proper growth and health of caulerpa, coralline, and other calcareous marine algae, and those invertebrates which have symbiotic algae living in their tissues. It contains a chelated form of iron which will stay available in the system for long periods of time, suppling algae in a timed release fashion, as needed. Directions: Add 1 teaspoon (1 capful or 5 ml) per 50 gallons (190 l) every week or 8 drops each day in normal systems. If particularly trying to grow caulerpas or other macro algae, Super Chelated Iron Supplement can be used at up to 3 times the rated dose, very safely