IMHO, your Alk is at a totally acceptable level, I wouldn't consider 9 dKH low, as typical NSW is 7 dKH, and 9 dKH is right in the middle of the recommended level for reefs. If your 2 Ca tests show 390-400 vs LFS at 580, I would lean towards your tests more than the LFS (2 out of 3, right?)...