API Replacement Test Tubes with Caps (24 pack) – A set of 24 glass test tubes with plastic caps, designed to replace lost or broken tubes in API aquarium water test kits. These durable, clear tubes fit all standard API liquid test kits and are essential for accurate water testing. Keep this bulk pack on hand to ensure you can continue monitoring your aquarium’s water quality for ammonia, pH, nitrates and more, helping maintain a healthy aquatic environment.