I use two ZooMed UTH's (which I keep one 80 and the other 90), a heat lamp in the middle using an infrared bulb (to maintain ambient air heat which is around 80), to read the temperature, I use Acu-Rite thermometers and to adjust the heat, I use lamp dimmers. The reason why I use a heat lamp is because I heard somewhere on the site that If you use only UTH's, it only gets the bottom of the tank , while the ambient air in the tank could be cooler when basically your whole tank should be in a comfortable warm state.