Here is an update with my levels, I haven't added to much, just a couple of acropora's.
Elos Test Kits:
Ca: 550ppm
Mg: 1350ppm
PO3: 0 ppm
API Test Kit:
dKH: 8
NO3: 0
I am going to go and replace the two API kits with something more accurate, but I am completely puzzled...