When you say "tray" are we talking Spanish cedar or plastic?
I have mine taped over...
The humidity up top is about 60-62% with 1 pound of 65% beads (add water all the time)
and at the bottom 66-70% with 1 pound of 65% beads in a tray, and I have some condensation issues. I dry out the bottom beads every few days (1sq foot tray)
Humidity is supposed to rise, but i guess my wine cooler denies all laws of nature!