Question with using the ADD on NAS product

[acdcking12]

So I have the Asustor AS5110T

What I would like to do is buy the 3 bay add on. But if I did this, could I only add one drive to this and add it into my Raid 6 and then add a 2nd and a 3rd as I get these drives and add them individually?

Or do I need to fill up all three slots initially and add all three to the Raid 6 at the same time?

[orion]

You should add one disk at a time to increase your existed RAID-6 volume. After done, proceed the next one. It takes long time. https://www.asustor.com/en/online/Colle ... topic=352.