Features: The product use new formula and technology, Carbon dioxide tablet is free from toxin, pollutions and suspended substance. It release carbon dioxide slowly into the water, supply plants right amount of carbon dioxide and do not affect the fish absolutely. It will help your aquatic plants to thrive. Method of Use: 2 times / week. Every 20L water use 1 tablet. Different parts in the for tank. (the best use of the proposed methods is the CO2 into the filter used together) Warm Tips: This tablet doesn'for t release bubble in the water. It will just melt slowly, and release CO2. Specifications: Color: As pictures shown Size: One Size Quantity: 1 Bag(10 tablets) Package Includes: 1 Bag CO2 Tablets (One bag with 10 tablets) note: Please allow 1-3cm error due to manual measurement and make sure you do not mind before ordering. Please understand that colors may exist chromatic aberration as the different placement of pictures.