Can I put Styrofoam around the terrarium and that could help insulate it would that work?Glad to see you changed the substrate, that looks much more suitable. Again the if you are comfortable they are comfortable rule would apply. That heat mat should be plenty as long as your house is heated. However, if it would help your worries, use a space heater to warm whatever room you have the t in.
At night usually usually gets down to 71