The ColorQ TesTab PRO 4 measures four basic pool and spa tests. As a bonus, the ColorQ TesTab PRO 4 can also measure Total Alkalinity [Code 3882A-J], Calcium Hardness [Code 3883A-J] and Cyanuric Acid [Code 6996A-J] with optional reagents sold separately. The photometer uses instrument grade tablets packaged in blister style foil.