Red Sea Phosphate Pro Test Kit - Exceptionally high accuracy colorimetric comparator tests for Phosphate measurement. Red Sea's Phosphate Pro Test Kit is an advanced colorimetric test with comparator, measuring the level of phosphate in your reef aquarium to an exceptionally high accuracy of 0.02ppm PO4. Phosphate Pro Test Kit, when used in conjunction with the Nitrate Pro Test Kit, enables accurate dosing of Red Sea's NO3:PO4- X (Biological Nitrate and Phosphate reducer) which is part of the complete Red Sea Reef Care Program.