Yesterday during maintenance Tuesday the pre filters for corner station LVEA HVAC units SF1, SF2, SF3, SF4, SF5, and SF6 were all swapped out for new ones. The new batch of pre filters Bubba ordered that were used in replacement are MERV-13. Which is a step up in more filtration by a factor of +2 from MERV-11 that the previous pre filters were. 
The pre filters at EY, MY, EX, and MX Supply Fan units, were all swapped out for new ones as well. These were replaced with older style but new MERV-11 level filtration pre filters. Unlike what was used to replace pre filters at the corner station LVEA units.