Below is all the ring heater changes while we are actively locking the IFO. Nothing in the box means the previous change remains.
Writng this diary to help decide if we can take some differential heating out of the Y-arm without ringing up any PIs.
Only TM changed since O3 is ITMY.
| Date | IX | IY | EX | EY | Reasoning |
| 2020/03/30 | 0.48 | 1.37 | 0.44 | 0.4 | O3 values |
| 2020/11/19 | 0 | 0 | - | - | ? |
| 2021/02/24 | - | - | 0 | 0 | ? |
| 2021/04/29 | - | - | 0.4 | 0.7 | 14.kHz PI 58813 58787 58811 Tried EX at 0.7W was not good. |
| 2022/04/14 | - | - | - | 1.0 | 10.4kHz PI 62623 62650 |
| 2022/08/11 | - | - | - | 1.2 | PI at 40hours into lock 64440 |
| 2022/12/15 | - | - | - | 1.4 | Maybe PI 66381 |
| 2023/01/13 | 0.44 | - | 0 | - | Attempt to offload CO2X Annular 66801 (CO2 test 66853) |
| 2023/02/01 | - | 0.4 | - | 1.0 | To match X-arm. 67174 Not good so reverted over 02/03-02/07 |
| 2023/02/07 | - | 0 | - | 1.4 | Reverted as cannot lock 67280 |
Georgia's CO2 test 66853 hints that a little less CO2X might be good but we didn't act on this.