6PIIFCE Water Quality Meter. Measure pH, ORP (with free chlorine equivalency mode), Conductivity, TDS, Resistivity and Temperature with this Myron L Ultrameter all-in-one water quality meter. The Ultrameter II model delivers performance of ±1% of reading (not merely full scale). This high level of accuracy has been achieved through advanced four-electrode conductivity cell technology, a unique pH/ORP sensor and powerful microprocessor-based circuitry. Ideal for water quality applications in cooling towers, hydroponics, wastewater, reverse osmosis and much more.