Max hard drive for usb 3.0 port?

So I want to add more storage using the USB 3.0 on the back of my 2 TB WD MyCloud, But can’t find any information on possible limits to what can be used with that USB 3.0 port. Anyone know where i can find this information, or just know the answer in general? I’m oping to use a 5TB Desktop expansion drive.

Look at the User Manual, Chapter 12, use link below. Don’t know that there is a size limit.