AS5002T "other" Storage Filling up Storage

[haavo]

On my AS 5002T NAS, my storage (3TB x two) has recently been filling up completely. When I look at the activity monitor, the storage area labeled "Others" keeps growing. It's now at 47.82GB. If I delete files in say my media folder, it recogonizes that here is more free space, but then the "others" part of storage gradually increases to fill up the total storage until I again have 0.00 B free. Not quite sure what is going on and I don't know where/how to find where the "Others" files are stored. I'm really not that familiar with the inner workings of the NAS, it's just used as storage (movies/movies/pictures) basically, I don't do anything complicated with it. Thanks for any help.