I leave the inner cover in place. I put a 3/4" block on top of the inner cover at the front then put the outer cover on top.It gives a better air flow by increasing venting where the inner cover has that little notch that does nothing more than give them another entrance. Two 1/4" blocks on the back corner increased the flow area by roughly 56" tapering front to back. Granted it tapers from 0 to a 1/4" but the fanning of the bees gets better flow. Other than water and air I don't do any thing else.