I have never heard of "Reptile Relief", so if anyone reads this and has some information on it, and treating mites, I'd appreciate that.
I think the best thing to do is clean the turtles environment thoroughly and let it dry out completely. There is a product called Provent a Mite that you can spray on to keep them away after you clean. I have never used this product so I don't know just how effective it is, but you could read the label and see if you can also use it on your boxies.
I would also rinse the box turtles off and let them dry good too. You mentioned that these are babies? You will want to use extra care for them. Read your labels, and if you have a good herp vet, call and ask about treatments. To find a good reptile vet, visit the www.arav.org web site.
Best wishes,
PHKiwi