I have a Pneumatech refrigerant dryer and plumbed it in between the compressor head and the tank to remove the moisture before it hits the tank. I've been told that desiccant will have a tendency to break down and can add impurities into the air system, possibly showing up as paint defects resembling small circles of delamination. So instead of desiccant I opted for the SATA filter system and being a tight ass I waited until finding one on CL for cheap. The nice part is this also uses the charcoal filter setup so I can use compressed air for the breathing hood. The filters are installed outside the both to keep them out of the overspray, the final regulator and shutoff valves/outlet ports are inside the booth.