Flourish tabs are growth stimulating tablets for plant roots. They contain essential trace elements, amino acids and vitamins. They are rich in iron, manganese, magnesium, calcium, potassium, inositol, choline b12, biotin and other factors that have been determined to be beneficial to aquatic plant roots. They contain no phosphate or nitrate that would promote algae proliferation. Each pack of ten tablets treats a 12 x 30 inch plant bed twice.