I have a small ball python in a 20 long aquarium with a uth under it. i checked the temp at the substrate with temp gun but it seems kinda cold. it is connected to a thermostat and the thermostat seems to be reading it at higher temps. also, i have a thermometer probe taped to the bottom glass above the heater and it reads in the low 90's. i have thinned out the substrate (coconut husk) but it still reads cold when i check with a temp gun. shouldn't the temp right above the substrate be in the low 90's? this is the hot side of course. any suggestions?