I have been using solid bottom boards on two hives all summer but would like to switch to screened bottoms this weekend. I have heard that this is better for cleanliness and Varroa control. My hive stand is a solid piece of plywood so does this defeat the purpose of the screen not allowing debris to fall to the ground? Does a screened bottom inhibit heating / warmth of the hive? If I do a powdered sugar dusting with this plywood stand will the mites simply return to the hive if not allowed to fall to the ground? Changing hive stands would be a task as I have done a lot to insure ant protection. I live in San Diego so temps at night are mid 50's and day time 70 - 80. Thanks