I've finally made a humid hide for my little sulcata, badly needed, but it's not warm enough. I put a heat mat on the side, but the temps are only in the mid-70's. I can't move it to a warmer spot in the enclosure. I tried to research it here on the forum, and several people referred to heat cables. Would it be safe to put heat cables in the bottom directly under the moistened coco coir substrate? Or does anybody have any other suggestions?