I have a Reptisun 5.0. for my hatchlings also, but I also have a sun glo basking spot light that gives off heat. Mine usually bask under the light that gives off the heat as their basking rock is under that one. When they get too hot, they will move to the other side of the tank where the Rep. 5.0. is and sit on their cave that is on that side of the tank, or go into the water.
Terry