I am returning to hobby beekeeping after a two year absence, so forgive me if things have changed or I have forgotten how to do things. I have two hives in an urban setting that I started last month with an Italian package and a Carniolan nuc, both from the same supplier. They appear to have started off well - healthy laying queens, drawing out comb well, etc.. I thought it would be a good time to treat for mites early - while the Italians were broodless. I use OAV and treat four times at 5-6 day intervals. I did the first treatment last week and another yesterday evening. When I checked the bottom panels this morning, I found absolutely no mites - none, zero, zilch. I scoured those panels with my LED magnifying glass and found nothing. Even if I totally screwed up the OAV, shouldn't there be mites that have fallen off bees anyway? I feel silly for questioning a no-mites finding, but it just seems incredibly unlikely to me that I should have no mites. What am I overlooking?