You put the thermoMETER probe on the substrate on the warm side (pref. under the warm side hide) and the probe of the thermoSTAT flush against the underside of the UTH.
I tape my stat probes directly to the underside of the UTH under the tank. I used to have them between UTH and glass, but it didn't work as well for me.
**Adriana - White 'N Nerdy!**
1.0 BP 'SunSpot', 0.1 Corn 'Freya', 1.0 IJ BTS 'Topaz', 1.0 ND bunny 'Licorice'