I have one of those "my first home" cages that was for my guinea pigs and is now a brooder.... it has a plastic base and a metal cage on top.... I have a question. How do you control the temperatures? I have it at 95 -90 but how will I be able to lower the temp? I have the lamp sitting on top the cage now but there is no way to lower or raise it.... what do you do to control the temps?