Freshwater Biozyme is a living system of beneficial bacteria in concentrated form, which is activated upon introduction to water. It converts lethal ammonia and nitrite to less harmful nitrate. It quickly reduces fish waste to inert substances and breaks down organic buildup in gravel beds. Freshwater Biozyme has unlimited shelf life, as opposed to liquid enzymes. These bacteria contribute to the production of the nitrogen cycle which is critical to all aquatic systems. This material gives you the option of increasing the activity of an already established filter, or reactivating a filter damaged by medications. Helps prevent "new tank syndrome" when used for establishing new aquariums. Directions: Use 1/4 teaspoon for 25 gallons of water directly in the aquarium. Every week, add 1/8 teaspoon per 25 gallons to avoid pollution and for nitrate reduction. Use only as directed. Slightly overdosing does no harm, but is not necessary. This product will be replaced or refunded if defective in manufacture. Except for such replacement, there is no warranty of liability-even if loss is caused by negligence or fault. Keep out of the reach of children. Caution: Not for human consumption. For aquarium ornamental fish use only. Not for fish or livestock used for human consumption. After opening, store in a cool, dry place.