ReeFlowersAquaPlants Liquid Carbon�contains a highly concentrated liquid carbon source.� It has been specially formulated for aquarium plants. Carbon is used during the process of photosynthesis and is one of the basic elements that plants need for development. Carbon deficiency will end growth and germination. ReeFlowersAquaPlants Liquid Carbon may be used as an alternative or as a supplement to CO2. It helps promote development and reproduction of micro-organisms living within the sand and water and prevents algae.� It also helps convert iron from Fe3+ (naturally found in water) to Fe2+ form, which is easier for plants to use.