ok, i got the concept of a hot and a cool side, now i just need to know where to take the readings from. i've been playing around with these gradients and could really use some feedback. i'm not 100% sure where to put the probes of my digital thermometer so i'm trying 2 different ways now. cage 1 has a juvi suriname in it now, and the temp prob on the hot side is taped dierctly to the heat tape under the substrate. when the dimmer switch is 1/2 way on, the temp is 105* - 110* at the probe. the substrate is slightly warm to the touch but it dosent feel much warmer than the cool end that is 78-84* day, and 73-78* night. right now the cool side is at 80 cage 2 is empty so i'm kinda playing around with that one. the dimmer switch is 3/4 on, and the probe is taped to the far right hand side wall (hot side) about 1/2" above the substrate. right now its reading out at 86* on the hot side, and 79* on the cool. so what seems right? should i try to make a bracket so the probe is directly above the center of the heat tape and just under the substrate? any input would be greatly appreciated. ~Will.