A lot of people give this product a bad rap, but it's really not meant to be used by itself. By following the label, you can target a specific pH when mixing it with Seachem Alkaline Buffer to create well buffered water. (It works best when your start with RO/DI water.) It should NOT be thought of as a cheap way to add CO2. It's carbonate based so it doesn't invalidate the CO2 chart.