Thanks for the reply Greg. My ALK (Hanna) yesterday was 10.08 dKH and today is 9.184 dKH. Perhaps i'm letting it drop too low and well beyond dKH which is why it was STN on those SPS. I'm going to try to keep it steady for a while and we'll see what happens at the end of the week when its water change time.

Also just checked my calcium and it is at 440 ppm (Salifert).