Water Chemistry

happy new year to everyone!!!!!!!!!!!!!

I am having some problems with my 65 gal reef. Over the last month I have seen a decline in my corals. I went to my fish store got some water tested. magnesium phosphate salinity, all came back fine ( i really trust these guys) I tested all the others nitrate 0 ammonia 0 calcium 400.
ph was off 8.5 here is the one I am confused about ALK my reading says it is in the ok area others I have talked to say it is low,my test kit is red sea ...