There are a lot of different ways people treat for mites and other pest insects and my own opinion esp if using the deep litter method is to use chemicals as little as possible as it will stay in your bedding and if you use the old bedding it in a food garden later it can transfer where it may kill off earthworms you'd want to keep,
I use DE (Diatomaceous Earth) and plenty of it, it is pretty much harmless to the worms as far as I know in damp soil but in the surface of the litter, on roost poles, in the nest boxes it will kill mites, ants and most any insect that gets in it, Just make sure you buy the "Food Grade"
I always make a place for the chickens to dust bathe in it or just add it to the areas where they make their own, Other than a couple of chickens that were fresh from a sale once I've never had mites on my birds, the sale birds were clear of them when I placed them in with the other chickens a couple weeks later and all I used was DE.
Bill (Stony Creek Farms) has a good video on how he does his coops I couldn't find the link it's been a while but maybe he (or someone) can repost it perhaps,
DE is safe as long as you don't breathe in the dust, I drink a teaspoon of it in water to help with joint pain and other things daily when I remember to LOL it kinda tastes like dirt but isn't bad and it helps, Lots of good info on the web and here on BYC also, If you are coming through or are close to Purcell I can give you enough to use I have a half of a 50 lbs bag left and no birds at the moment so can spare it