DX4000 - Rebuilt Drive Status = New Drive

I have a DX4000 with 4 X 3TB drives in a Raid 5 running firmware I have been running with one drive at Imminent Failure for a little bit and had the joy of another drive failing completely. Raid is still operational and there has been no data loss and am now trying to replace the failed drive. I ran out and purchased a WD Red Pro drive as it was the best option i could find in a store nearby. Inserted the drive and received incompatible drive message. Went ahead and installed the drive enabler patch and re-inserted drive and rebuild started successfully. My concern now is that the newly inserted drive is sitting at a status of “New Drive” and not “Normal” so i am concerned about it being part of the RAID. I would like to replace the other drive that is in Imminent Failure status but not feeling to confident in pulling it out before i am confident that the recently replaced drive is stable. At this stage it shows my total capacity is just under 9TB’s so it seems like the 4 drives are all in production. Looking for any input on why this drive may be staying at “New Drive” and if it is safe to replace the other failing drive.

use dskmgmt.msc to see the drive layout. Should be just one large volume
go to the alerts from the dashboard and delete and alerts (right click)

No clue, either an old alert is in there or it will say normal after the rebuild is complete