Rhp's are awesome but if you want belly heat I would use a Kane heat mat. The Kane mat is designed to be used in enclosures, they are water proof and really heavy duty. They are even used outside in barns and such for animals. I use a rhp and Kane mat inside my vision v400 cage and its the perfect combination for my weather conditions. The only thing is that the Kane smallest size is 18x18 so your tank would have to be around 3x2 or 4x2 or bigger, anything smaller and you wouldn't have much of a cool spot left.