Ron

[Ron]

Added a new disc to my pool
How do I get it to balance everything out so that there’s files on it?

[Shane]

Do you have Automatic Balancing turned on (from the DrivePool app, Manage Pool -> Balancing...) and what is the Triggers section set to?

[Christopher (Drashna)]

It should be noted that when adding a new disk, StableBit DrivePool does NOT rebalance the data in the pool to use the new disk, immediately.   This is ... unnecessary and over time leads to a lot of unneeded/unnecessary writes/moves.   

Over time, it will use the drive, as new files are placed on the drives with the most available free space (and the new drive is likely to be the primary candidate for that).  

However, if you are insistent on rebalancing the data to the new drive, you can use the "disk space equalizer" balancer.  It is disabled by default, but enabling will rebalance the data on the pool so that it's similar usage between all of the drives.