Just a quick note for anyone who is entering a nectar flow season with previously used Flow frames. Please, please, please check the wire tension! We just supered one of our hives, and I inspected the Flow frames before supering. The wires were really pretty lax. They were tight last time we harvested, but I guess that turning the key stretches the upper wires a bit. I just thought that it might save some heartache if I suggested that you check and tighten before letting the bees work the frames. It only took me about 20 minutes to do 6 frames, totally worthwhile.
This only looks like a millimeter or two, but the frame flexed quite a lot with gentle pressure. So please check yours before letting the bees use them!