Advanced titration test measuring the level of calcium in your reef aquarium, with exceptionally high accuracy of 5 ppm Ca Red Sea’s CALCIUM PRO Reef Test Kit is an advanced calcium titration test, measuring the level of calcium in your reef aquarium to the exceptionally high accuracy of 5 ppm. This test kit enables the accurate dosing of Red Sea’s Reef CALCIUM + Foundation A (calcium/strontium) and Trace Colors supplements, which are part of the complete Red Sea Reef Care Program.