Features:This tablet will increase CO2 content of fish tank,which will improve photosynthesis efficiency and plants growing.It is important for fish breeding as well,better living condition will offer your fish a great growing.Better to use with CO2 atomizer Rapid effect,quick solution,easy to absorb,safe and no harm. How to use: Approximately 20L water uses one piece of this tablet,and twice a week(place on different position of fish tank). Specification:Type: Fish Tank SuppliesColor: As pictures shownQuantity: 1 Bottle(tablet only,other accessories demo in the picture are not included ) Note:1.Please allow 1-3cm error due to manual measurement. pls make sure you do not mind before you bid.2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you Package includes(without retail package):1 Bottle x Tablet