During commissioning today I looked for the source of the 13.1 Hz harmonics that began to appear on Oct. 3, by testing some of the things that were done that Tuesday. First  I temporarily shut down the DC-DC converter and oplev laser for ITMX that had been worked on. But the noise, likely from the very high microseism, made my tests inconclusive. I also tried disconnecting the new grounding on the TCS and PSL chassis. Since DARM noise was too high for me to tell if this helped, I have left them disconnected and will reconnect the grounds when we can tell that they are not part of the problem.