The 3TB drives are running as 2 due to drive size mismatch a raid array with different drive sizes will sizes will configure to the smallest drive size.
That particular card will need to be flashed to IT mode to ensure HBA
That would be the simplest way of doing it, otherwise you would have to replace each 3TB drive in turn resync/rebuild the array, once complete 'grow' the array and then the file system to get the maximum capacity.
So I kind of solved my own issue. I bought the M1015 card, flashed it to LSA IT mode and then replaced the 2tb drives with the new 3tb drives and then expanded my pool. All drives and TBs are showing and available