I've used a combination of two small light domes but zoo med's mini combo deep dome lamp fixture is probably better. I'm a fan of the zoo med bulbs and the daylight blue is good for day time heating, then switching to their red bulb at night. You could also use the red bulb for 24 hours and instead use a compact fluorescent. Just use whatever wattage reaches at least 78F on the floor and no more than 84F but allow for a night time drop to around 72-74F at night. I've used between 40-60Ws but they do dry the tank out some but you can just mist every day to compensate. I'm currently just using a thermostat-controlled heat mat under a third of my tank because it does the job without the drying effect and I'm using exo terra's led day and night for lighting.