Seachem Flourish Iron is a highly concentrated iron supplement for aquariums with live plants. Its simple, pure formula is ideal for iron deficiencies and/or situations when iron requirements are greater than what Seachem Flourish can provide. Iron supplement for the planted aquariumHighly concentrated (10,000 mg/L) ferrous ironContains no phosphate or nitrateFlourish Iron contains 10,000 mg/L of ferrous iron (Fe+2) gluconate, a highly effective form of iron that provides greater benefits than ferric state EDTA-iron (Fe+3) sources used in other iron supplements. Plants can only utilize iron in the ferrous state, and must expend extra physiological energy just to make ferric iron supplements usable. Flourish Iron provides plants the iron they need directly, saving time and reducing stress on your plants. Use Flourish Iron in those cases where iron requirements exceed that which can be delivered by standard Seachem Flourish at the recommended dose, or when signs of iron deficiency appear (including short, slender stems or yellowing between veins). Directions: Use 1 capful (5 mL) for each 200 L (50 gallons) of water, or as required to maintain about 0. 10 mg/L iron. For smaller doses please note that each cap thread is about 1 mL. Use a test kit to monitor iron concentrations. Use as needed to combat signs of iron deficiency (usually seen in new growth). Guaranteed Analysis: Iron (Fe) - 1. 0%