Keep your aquarium thriving with the Farrinne JBL Proaqua Test No2 Refill. This 100 g refill is essential for accurate nitrite (NO2) testing, allowing you to monitor and maintain a healthy environment for your aquatic friends. Compatible with JBL Proaqua Test kits, it provides precise readings, helping you ensure optimal water conditions and prevent harmful nitrite spikes. Perfect for hobbyists and professionals alike.