Try a 60 W "red bulb" from your LPS. You can get a small light fixture from lowes, homedepot, or even walmart for about 8 bucks (the one that has a clamp for it and says max wattage 75). We suspend ours about 5-6 inches over the tank and the temp sits at 83-87 F. You can also use a UTH (under tank heater) and secure it to the side of your tank for extra heat.