No way to check a FS on an Areca controller

Hi everybody! This is my first post though I been here for a while. My problem is that I can't check the file system on an Areca controller with a 4 disk raid5. After one disk died and the controller rebuild the raid 5, OMV sees a file system problem on the Areca; when I try to umount the sda (the Areca controller), system tell me that it's in use and have no way to unmount it to run a fsck. All the info on the raid and is accesible, but I have to fix the file system.

Thanks and regards!!

Thanks, ryecoaaron! Let's see.....

I ran on systemrecuecd and fsck found a error with superblock and advise to run with other sizes (8000 and 32000) but none of then work either.....

Any other idea will be really appreciated!