It's up to you but GoFiltr is designed to be left in your bottle, some customers prefer to take it out. Leave it in and keep refilling. Once water reaches optimal pH level, GoFiltr is designed to slow down alkalization process, extending its lifespan. Though, ionization process will continue, keeping your water ionized. If you prefer taking GoFiltr out then we suggest doing so after 15-20 minutes, this way your water will have optimal pH and ionization level.