It shouldn't be too high with a 75 watt bulb. We use actual heat bulbs and don't have a temp problem. I'm assuming you have a basking spot. Where is it located and how far away from the light source is it? Also, where are you measuring the temperature? It should be warmer towards the top and cooler towards the bottom. So if your thermometer is near the middle/bottom of your cage, it will read much cooler.