Rinse pouch under tap water. Place pouch in path of water flow in the aquarium filter. For a new aquarium or when ammonia or nitrite is detected: recharge every 5 days for the first month, and then every 2 weeks for the second month. For an established aquarium: recharge every 2 weeks. When nitrate is detected: recharge every 5 days until nitrate is reduced to 20ppm (mg/L) or less. Replace pouch after 2 months.
To recharge, dissolve 4 tablespoons (80 g) of API AQUARIUM SALT in 8 oz. (240 ml) of warm tap water. Soak pouch for 2 hours, then rinse lightly in tap water. When not in use, store pouch in recharging solution.