Wait, what?? Flexwatt is illegal in Canada? For what reason?
Edit: When you do lay down whatever heating element you choose, do not heat the entire surface. They need to be able to get away from the heat in order to regulate their own body temperature. Also if for any reason it were to get too hot for them they need to be able to escape the heat or risk physical and neurological damage. Most people will say heat 1/3 to 1/2 of the enclosure. I heat 1/2 of my tubs.