I've just set up an AP T-8. I've got a Fluker's Large size UTH under the hot size. It's connected to a hydrofarm proportional thermostat. Probe is in the probe slot, sandwiched between the underside plastic and heat mat. Here's the problem: I've got the thermostat set at 104F and the internal belly heat PVC temp is only 80F. I've tried airflow underneath and styrofoam underneath with minimal change.
Has anyone else experienced this issue? How can I get more of the heat into the tank?