Hi, I've just RMA'ed my 1TB external drive. It is full of our family information. Therefore I picked 3-pass Secure erasing before shipping it out. DiskUtility on my rMBP is working on it since last night and it has 24 hrs to go. Is this an OK estimated time? Seems too long to me. I cannot imagine how long it would be on 7-pass or 35-pass secure erase. Thank you!