how is co2 obsorbed by the plant is it through the roots or the leaves if its through the roots is it possible to add this stuff http://www.seachem.com/products/product_pages/FlourishExcel.html i use it in my aquarium for my plants as i dont have a co2 set up for them to survive and adding this stuff in there helps alot as i have plants in there that are 8months old usaully they only lasted me about 2 weeks, so will adding this stuff when watering help the plants get co2 or will it end up killing them