New, additional drive in EX4100 shows red light on NAS

I recently added a 4TB WD Red drive to my EX4100. The EX is set to RAID 5. The first three 4TB drives in bays 1,2,&3 worked right off the bat. When I installed the new Red HDD the bay light remained red. The dashboard shows all four drives as okay but does not display the S.M.A.R.T. data for the new drive. The dashboard shows there’s a single volume.
What options do I have? I already have almost 6TB in use, with 3.6TB free (should not that free be higher as all three existing drives are 4TB?)

Thank you for the information but it neglected one tidbit. How does one initialise a hard drive for an EX4100?
I can nothing specific in the manual nor on the support site.

You’re right. Not at all intuitive or easily found. Now to wait the
1550 minutes.