One of my hives has almost filled up their first medium super with honey. I checked it yesterday night. Twelve days ago, this super had only undrawn wax foundation. As of yesterday, they have filled all 10 frames with honey, but currently 90 - 98% is uncapped. In the center frames, some of the cells have fresh caps on them - it looks like the bees are just now starting to cap them. Would this be a good time to add a second super, or should I wait until most of the cells in the first super are capped off (I read "80% capped" somewhere)? If the latter, how many more days should I wait before checking again? I don't want to wait too long and have the bees start thinking about swarming.