sounds like the water is evaporating from the water dish like someone else already mentioned . . . move the water dish as far from the heat pad as possible if you havent already that will definately help . . . you said you have drilled hole after hole, how many holes are currently in the tub? . . . maybe drill some more holes . . . if you drill too much and the humidity is becoming to low you can always plug a few holes back up


P.S. nice looking spider!