So, please monitor your mites and treat if necessary.
This webpage from the Honey Bee Health Coalition is one of the best resources for understanding how to monitor for mites and includes information about the best options for treatment based on time of year or condition of the hive. There are great demonstration videos in addition to the pdf with an abundance of information.
http://honeybeehealthcoalition.org/varroa/
This is a not-so-great video I took in 2015 of state bee inspector, Don Hopkins demonstrating a sugar shake.
https://www.youtube.com/watch?v=enErclvPK58