Richard Pendered

Not sure which Recycle bin to remove (the individual drive, or the pool itself)? I've cleared the individual drives, but there seems to be 16Gb in the pooled recycle that I am not sure that i want to remove/lose. Did a checkdisk and now have a weird issue where a disk is lost, but is able to be added. See screenshot below. I'm not sure how I can move forward with this without creating a new pool and moving data manually. If someone can give me a steer that would be a help.

Drive Pool gives me the following error and I have no idea what to do to rebuild my pool.