BENEFITS: Scientifically proven to remove ammonia and nitrite to reduce the risk of fish loss when starting an aquarium. Also reduces nitrate in the aquarium. NITRA-ZORB can be reused after it is recharged in a salt solution. WHEN TO USE: When starting a new aquarium or whenever ammonia or nitrite is detected. Also, use whenever nitrate measures above 20 ppm(mg/L). Made in USA