Looks pretty! The covering of the sides is nice to give her more security. If that's just a screen/grate top then I can't imagine her humidity is at good levels, though. You want them to be at least 60%. A digital hydrometer is better at measuring than the highly inaccurate dial one. What are her hot side and cold side temps at, and what's her ambient temperature? And how are you measuring these temperatures? All of these aspects are very important.
An active BP can indicate a stressed BP. If this cage is bigger than her last that can stress her, or you could consider getting her another hide - one for the hot side and another for the cold side. The current hide she has has a big entrance, so it may not do too much to make her feel snug and secure. Usually aspen makes them feel a little more secure as they can burrow in it a bit. As far as mite prevention and using any chemicals - I can't help with that, I've thankfully never had to deal with mites and I just use newspaper and plastic hides.