the element from a styrobator is only about 30 watts. You probably need 60-80 watts to get that going properly
you can try running a 40 watt light in it continuously and use the element to actually control the temp. If you have a work light type lamp,try running it inside as an experiment.
another option is to use
you can replace the styro element with this one.
i use one of these in my bordeaux bator. in the phils lights seem to burn fast so i am using these to replace lights.