Use 71 grams (2.5 T) of Plantex CSM+B to one liter of distilled water. Use 1 cc per 2 gal to raise Fe 5.0 ppm. For example a 20 gal tank gets 10cc (two cupfuls) Dose daily, biweekly or weekly depending on bioload. You will get to be able to recognize plant behavior to know when to add more. Some species such as Cryptocoryne require an absurd amount of iron in the water column.