Repeated Drive Failure in SCSI Configuration

A week ago my Adaptec RAID 5 utility reported that a drive had failed and that the hot spare had been used to rebuild the array.  The failed drive (a Seagate ST366706lw) was at address 1.  I shut down system, replaced #1 with a new drive.  System recognized the drive, but formatting failed.  On Friday I got a new drive in place, system recognized drive, formatting was successful and I added it as a spare.  On reboot I could see #1 listed correctly as a hot spare to the array.

Now the drive has failed again, having lasted only about 5 hours!  These are new drives, and the array drives are all the same ones, and they have been reliable, up to now.  My question:  Could it be that the Adaptec 2100S is somehow destroying the drives?  Would it help if I used another address?  I just find it hard to believe that two new Seagate drives in a row, from different sources, would be bad.