LS-QVL284 added two drives; can't see them

[pmat]

I've got two Linkstations. The problem with the LS-QVL284 arose when I added two new hard drives. Previously, I installed two in December. They installed correctly and worked properly. Recently, I added two new drives (same models as the original two). This fills the NAS. I believe I followed the correct procedures, and eventually, the 2 original green lights on the front, were joined by the two lower lights. This I thought meant they were working. However, they do not appear in the NAS Navigator and when I log in as admin via browser, the new drives don't appear. Any suggestions?

By the way, both the LS220 and the LS-QVL are accessed by different browser screen displays when I login via their IPs. I had originally assumed they both would be accessed by the same screen display version.