To sustain healthy plant growth, your aquarium must offer a number of trace elements, including potassium, Sulphur, manganese, and most importantly, iron. These elements are constantly replenished by the currents in a natural environment, but they can rapidly become depleted in a closed environment, such as an aquarium. Healthy growth will be impaired by a shortage of any single trace element, though most critically by a shortage of iron, which is used in the production of chlorophyll, essential for photosynthesis. BIOVERT provides all the trace elements you need to ensure healthy plant growth. The iron is directly bio-available and assimilable by the plants. (Fe II). Use BIOVERT to remedy poor plant growth and yellowing, splitting or transparent foliage in your aquarium. BIOVERT is nitrate and phosphate-free.