>Maybe this wasn't addressed to me but I'll add a comment to it.
It's not addressed to any in particular, but sometimes people think something is ineffective because they don't see a noticeable drop in the mite population. Sometimes not seeing an INCREASE is an improvement. :) But the other point is that it is much more effective to treat when there is no brood, if you can plan that either ahead or arrange that.
On another note, a good time to arrange that is just before the flow. If you confine or remove the queen two weeks before the main flow then when the main flow his there is no open brood. In another week or so there is no brood at all. If you're using powdered sugar you can treat with that, then, and you can enjoy a better harvest because of the nurse bees being recruited for the flow, and you get a break in the brood cycle. Release the queen (or if you removed her, just let them finish rearing theirs) and you now have a lot less mites and a lot more honey.