Effective Filtration: Filters include activated carbon and ion exchange resins that help remove chlorine, odors and contaminants, effectively filter dirt, encourage your dog and cat to drink more water and promote animal health and hygiene. EASY TO INSTALL: Rinse the fountain filter 3-5 minutes before use. Keep the filter completely wet to remove carbon dust and keep the flat side up for optimal filtration. Then the installation is complete. 2-3 Week Change: We recommend changing every 2-3 weeks to ensure the best protective filtration for our pets.