Reef Master Test Kit by API $39.99 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity We are currently experiencing temporary outages for select pet products due to vendor shortages out of our control. We may contact you after placing your order to make substitutions or to update you on your order. We apologize for any inconvenience this may cause you. Add to cart Measures the most important aquarium levels. Tests calcium, carbonate hardness, phosphate and nitrate levels quickly and accurately. Calibrated specifically for reef aquariums.