Isis, this is very important. If you have no dimmer switch or thermostat to control your heat pad then as a very temporary fix you could just make sure that the bottom of the tub is not sitting directly on the heat pad. You could prop the tub up about a quarter of an inch or so above the heat pad so there is some air flow BETWEEN the heat pad and the bottom of the tub. You could use strips of wood or maybe those little funiture pads with the sticky backs to elevate your tub above the heat pad until you get a thermostat.