The ColorQ Pool 4 measures four basic pool and spa tests, Free Chlorine (0 to 10 ppm); Total Chlorine (0 to 10 ppm); Bromine (0 to 22 ppm) and pH (6.5 to 8.5 pH). As a bonus, the ColorQ Pool 4 can also measure Total Alkalinity (Code 7038-G), Calcium Hardness (Code 7041-G and 7042-G), and Cyanuric Acid (Code 6996A-J) with optional reagents sold separately. The photometer is easy to use and features economical liquid reagents for 144 tests.