If you've got a digital thermometer with a probe already, I would get a rheostat, it allows you to adjust the temps in relation to room temperature. You can also apparently use a light dimmer for this. I don't know how you do that, but if you do a search for rheostat I bet it will come up. A lot of commercial rheostats have generic low, medium and high settings, so you have to play with it a bit, but definitely get that warm side temp down to about 29C.
Have fun!