I used 'mite solution' for the first time last fall.  Prior to its use I
had lost 23 of my 30 hives to Varroa mite.  Although I had earlier used
Apistan, I did not want to continue using it.  I placed the mite solution
in with grease patties in the fall, again this spring.  A month ago I
checked for Varroa, both in drone brood and with Apistan with sticky
boards, and found NO Varroa.  I don't know why it works, but from my
experience, it does work, and the bees are once again healthy and busy in
our gardens.