Filter Fan Stand

My wife has COPD and moving into this older apartment was harder on her than we thought. Instead of buying a crazy expensive whole home filter, we just got some 3M MERV 12 20x20x4 furnace filters ($70 for 2) and taped it to a 20x20 box fan ($25). It works GREAT, but it needs to stay elevated to work well. When vacuuming we will just move the filter from room to room to let it collect the dust when the room is completed, but when just running naturally we've found that it helps to have it jus