Exactly. Don't pay attention to the crud written on those pads...most of it is seriously outdated.
However, do make sure that whatever heat source you use is no more than 1/3 the length of the tank, as was said. If it fits those dimensions, go ahead and use it.
Mmmh, is 8 x 18, the tank measures 30 long, is more than half, so there's no way I could use it ? Maybe in the colder months ?
Not even with the thermostat?