What are your basking temps? What brand and type bulb are you using for the UV? You may not even need the red one. The 100w white light should probably put out enough heat for a basking spot depending on the distance. They actually prefer something bright like the sun since they're from the desert. How are you checking the temps? You want to make sure it is between 100º F and 110º F in the basking area. Some people use the red heat lights at night but most say the light bothers their sleep. Its better to use an under tank heater or ceramic heat emmiter but only if it gets below 65º at night. If it's a new bulb, I know it wasn't cheap, you might want to return it.