| Date | Value |
|---|---|
| Jul 18, 2017 21:58 | 0.00 ppm |
| May 25, 2016 18:44 | 0.20 ppm |
| May 21, 2016 19:08 | 0.25 ppm |
| May 19, 2016 19:24 | 0.25 ppm |
| May 17, 2016 19:13 | 0.25 ppm |
| May 14, 2016 16:58 | 0.50 ppm |
| May 12, 2016 19:57 | 1 ppm |
| May 6, 2016 15:06 | 1 ppm |
| May 3, 2016 19:23 | 0.25 ppm |
| Apr 27, 2016 17:37 | 0.40 ppm |