Thank you for the help carlos! So far, I have had the best luck with a 60 watt heat bulb. The 50 watt wasn't warm enough and a 75 watt had the temperature in the tank up to 90 degrees. With the 60 watt, the temp remains around 80 degrees. I see on the white's care sheet that 85 degrees is recommended so is it better to be a bit lower at 80 or higher at 90? Confusion!