I have a fluorescent fixture with 4 bulbs over my 10 gallon terrarium. There is a hole on the top, so I have a Radio Shack cooling fan on top of the fixture aimed down thru the hole to create some airflow. The fan, of course, blows full strength all the time, but I would like to be able to alter the speed so it's not blowing quite so much. Does anyone know a good way to do this? Would a fader/slider switch (used for home lighting) do the trick? Or would the fan overheat if not running with the proper current?