I shut down the HEPAs in the ante room and in the laser room, shut down the 2 ACs (though I could not see their effect, so they could be left on) and set the makeup air at 30%. Overnight the temperature on the table increased by a couple to several degrees. The IMC was still locking, though very poorly. Paul tuned up the alignment  of the IMC and the REFL_DC level returned to better than it had before the change (about 50 counts). The figure shows a comparison of IMC_F  and the accelerometer at the top of the periscope in the two modes.