If you have a sealed grow box, and it is small, you may want to consider some muffin fans, like the ones for computers. They are small, quite and cheap. they may not be the best or strongest but the can move quite a bit of air. Brothers grunt has a sticky in grow room designs that shows how to wire them, check it out.
You can get these at computer stores or online at my favorite place in the world...Ebay. People who read my posts must think that I work for ebays marketing department, because I tell everyone to get things there, but it is really because I get like everything from ebay, I am an addict.

but the first step is admitting that you have a problem
Good luck on your grow, if you ever need any help do not be afraid to ask.
Peace