Replacement of Hard drive in My Book Dup

I am would like to know if it can replace one of my hard drives which is a WD30EZRZ Green with a WD30EZRZ Blue… these are 3TB drives… I lost one out of two drives… Thanks

This is not recommended. The RAID volume could fail since different hard drives do not work as well together in RAID volumes.

Should I just replace both drives with blue ones?