Herdo

As I said in the title, I tried to replace my cache drive as my current one has been showing some SMART errors.  I followed the instructions, but it says a "btrfs device replace will begin" but that never happened.  I was left with a blank unmounted drive that needed to be formatted.  I formatted it but it still didn't copy over the old cache drives data.  Now I'm stuck because trying to remount my old cache drives tells me that it will overwrite all data on the disk when I try to start the array.
 
What do I do now?
 
EDIT: Nevermind on the not being able to remount my original cache disk part.  I realized what I did wrong and was able to remount the old disk.  Now I'm just still not sure how to proceed with replacing the drive as the instructions given in the FAQ don't seem to work.
 
EDIT 2:  Nevermind again.  I saw that in 6.9 this feature didn't work automatically so I followed the instructions to do it through the command line and it worked perfectly!