When I had my sliders I found that the light from regular bulbs (not flourescent) worked fine for out of water heat. I had a regular hood that took the small incandecent bulbs. Only downside was that the bulbs did not last long. For water heat, I used a regular submersible heater. When I upgraded to a larger tank, I could only get a hood that took flourescent bulbs. Rather than go with the more expensive 'reptile' lights, I placed a small task light outside the tank pointed toward their platform, which seemed to work alright.
One thing to consider with a heat light is to ensure that you have a glass / plexiglass separation between the light and the main tank. With a heat light (or any other light) the water will evapporate. Mineral deposits will get trapped on the light surface and may smolder when the light is turned on; having a separtation will help to reduce this.
Last edited by Dogastrophe; November 13th, 2005 at 11:26 AM.