I have set up my terrarium, and think I have figured out my humidity problems, but now I am faced with temperature problems...

The temperature in the habitat was hovering around 70F all day and night without going above 75F. So I went out and purchased two heating pads, zoo-med 10-20 Gallon heating pads, and the temperature on one side of the tank now goes to around 80F, but the other side of the tank is now hovering around 65F-70F. Should I place heating pads on both sides of the tank, or is this good to have that much of a gradient in the tank?

BTW, I also keep a 5.0 UVB light on during the day, and a 40W Red Night Light on at night for heat and viewing light.