The problem is probably hot air, not time spent painting. If your compressor is runnning while you paint the air it is producing is hot and will not release its moisture into a moisture trap until it cools. I run a small auto shop and we have air lines plumbed into several spots in the shop. At each air outlet we have a water seperator, the air at the outlet has traveled away from the compressor and has had time to cool, thus seperating the water out more easily at the outlet. If the water seperator was attached to the compressor it would hardly collect any moisture because the air leaving the compressor is hot; after this air cooled, water would then puddle in the lines after the seperator.
I can pobably help you engineer a more effective way of seperating water from your compressor; you should never need two moisture traps, not even if you live in Florida. E-mail me and we can discuss your present set up and maybe figure out something better.
N.