Drive moved to another device pool

We're using BE 2010 R2. We just purchased 6 identical USB external drives. 2 for DAILY and 4 for WEEKLY. One DAILY and one WEEKLY drive plugged in every week and they're rotated weekly. We created 2 drive pools: DAILY POOL (includes DailyDrive1, DailyDrive2) & WEEKLY POOL (includes WkDrive1,2,3,4). For some reason BE detects DailyDrive1 and added it under WEEKLY POOL. We're using B2D Folder. What would be the way to set these drives accordingly. Any advice would be much appreciated? Thanks.