1. 1 pH observed with Honeywell pH electrodes Current Plan for Calibration and Cleaning Gel replacement Checking with Buffers pH: SATURN-03; SATURN-04

2. 2 pH vs Temperature; SATURN-03 BC = before cleaning AC = after cleaning Calibration Analysis eleven times from 20120917 - 20130104

3. 3 Percent Drift SATURN-03

4. 4 pH vs Temperature; SATURN-04 BC = before cleaning AC = after cleaning Calibration Analysis six times from 21021002 – 20130107

5. 5 Percent Drift; SATURN-04

6. 6 Current Calibration Plan (including gel replacement) Calibrate once monthly, record pH before and after cleaning and track adjustments made Check in buffers at least once weekly before and after cleaning Track data and look for trends and when to replace gel