Blue-green algae takes away from the beauty of any freshwater tank and can be difficult to remove. This blue-green algae remover gets rid of this algae quickly and is safe for use with freshwater fish and plants. No home aquarium should be without it. Thoroughly mix 2 level spoonfuls (included) for each 15 gallons with a small amount of water from the aquarium to be treated. Pour dissolved solution into the aquarium. Repeat after 48 hours if necessary. Wait at least one week before additional treatments. Note: May effect pH , ammonia and oxygen levels.