This booster contains live bacteria that accelarate the development of your biological filter to increase its effectivity. The result is your aquarium will maintain cleanliness for longer organic waste will be broken up & ammonia / nitrite reduced. This treatment also helps with floral growth after a medicated treatment. you should use when starting a new aquarium & each week thereafter. Useful after an excess of organic matter has been released into the water such as when caused by overfeeding / mortality also with new fish after cleaning of the filter & medicated treatment. Safe for your fish & plants. Shelf life of 5 years. Use in fresh or saltwater. 237ml