I purchased a hive that a fellow built and he sold me a bottom board with the hive. When I place the deep on the bottom board there is 3/4 of an inch of space for the entrance across the front. This seems like way too much space would be hard for them to defend. Is there some kind of entrance reducer I need to get or build to fix this?
The hive:
Bottom board entrance space:
Also the under side of the top cover has some gunk on it is this normal? Should I burn this off somehow or just wash it with some bleach looks like a bit of mold:
Thanks!
The hive:

Bottom board entrance space:

Also the under side of the top cover has some gunk on it is this normal? Should I burn this off somehow or just wash it with some bleach looks like a bit of mold:

Thanks!