What 4tb hard drives are recommended for the Drobo 5D? Right now I have 4 4tb Seagate ST4000DM000 drives in my media box, and was thinking of just inserting those into the Drobo, but someone said I needed to use a tyre NAS hard drive versus a desktop drive. This Drobo will function as my itunes media library, and a few miscellaneous backup files. Recommendations are appreciated, but I am not on a budget where I can spend $1500 on hard drives. Thanks in advance.