Flourish Tabsâ„¢ 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. Perfect for the beginner, Flourish Tabsâ„¢ contain all the nutrients found in Flourishâ„¢ in a dry, tabular form. These tabs are inserted into the gravel, providing direct, time-released fertilization to the plantsâ€™ root zone. Nutrients are slowly made available through enzymatic action of the plantsâ€™ roots on the tabs.