Flourish Iron, 2 L / 67.6 fl. oz. Iron supplement for the planted aquarium Highly concentrated ferrous iron gluconate supplement Should be used in cases where iron requirements exceed that which can be delivered by Flourish at the recommended dose or signs of iron deficiency Because Flourish Iron is in the ferrous state, plants more easily derive a benefit than from EDTA iron by not suspending energy 250 milliliters treats 50 US gallons for 4 to 6 months