First year beekeeper here so please excuse the newbie question. So today I finally had a little break in the weather to inspect my hive. First off they seemed to have wintered very well. I got my bees last May. I started out with a 10 frame deep and added another 10 frame in late summer. Today top deep was almost full of drawn comb, honey, eggs and capped brood. I haven’t ever checked for mites with a sugar shake but decided I would just treat for them before the honey flow starts. Question is how quick does it work? Reason I ask is I have a freeman screened bottom board and just went back a few hours latter to make sure the top cover was secured. I checked the tray and I could already see dead mites floating around.