Just thought I would share this..
I have been using division board feeders. They have a solid cover, and then two a mesh screen "tubes" that are supposed to prevent bees from drowning. Ha Ha. Had I known, I may have bought different feeders, but now I don't want to just toss what I have...
So- I cut small squares of wood block to put into each hole- like a float. I guess you could use cork or styrofoam too. Anyway- since then, I have had very few drowned bees, and it makes it easy to see how full the feeder is, because you can see the "float" right away.
Hope this comes in handy to anyone else with the same issue. Was a cheap, easy fix to a really frustrating problem