I’m not surprised the bees didn’t fill the flow frames. They didn’t fill the frames in the two boxes below the flow frames so they had no reason to move further up. If you look at the flow hive channel, you’ll see they put the flow frames directly above the brood box. They don’t recommend placing it so far from the brood box. Australian beekeepers tend to only have one honey super placed directly above the brood box, then remove and replace when the super is full. So I’d suggest you place the flow frames on top of the brood box and only have those two boxes in your stack. Also, feed your bees 2:1 sugar to water as early in spring as possible to prompt the Queen into laying eggs early.
