I use all 8-frame mediums, but I'd like to have the equivalent of a 5-frame medium nuc to use for starting splits or small swarms. Rather than buying 5-frame medium nuc boxes, I'm thinking of reducing the space in 8-frame mediums somehow. I could just put in a divider, but I'd like to fill or seal off the excess space so that hive beetles can't lurk in the areas that the bees can't reach. My first thought is to use an appropriately-sized block of styrofoam to fill the space that 3 frames would normally occupy. Would this work? Is there a better or easier way to do this?