As Lindsey has said you need a lamp with a dimmer switch so you can accurately control the amount of heat and light produced from the bulb. Also as a precaution when using heat lamps purchase a bulb that's wattage is no lower than 25 watts and no higher than 50 watts especially for a 10 gallon tank. Fallow these instructions and you shouldn't have to worry. Also 80 isn't a bad day time temp as was also stated above.