Clueless first time owner. Help Please?

[Romain]

Hi everyone my name is Romain and I'm a first time snake owner. I have a Ball Python I got from Petsmart. My snake seems healthy except I just discovered the tank has mites now. I don't know how they came to be if its from bad care please don't bash me I'm truly trying to make everything like a professional owner would. Im going to buy some mite spray and use it on the snake and bleach down the tank and wash everything down thoroughly etc. But I also noticed a few days after the first shedding of the skin that it was missing some scales. I've read that it could be caused from the top of the tank scraping them off idk just wanted everyones opinion on that. Thanks for the help in advance!
http://s1019.photobucket.com/user/rd...a9eb5.jpg.html <-- Hope you can see the image of the missing scales I used my iPhone