Test results today, pre-water change (it's been a few weeks):
Alk 4.8 - still low, need to adjust the dosing level up. Then again, nothing in the tank seems to mind it being low at all ...
Calc 460
Mag 1060 - think a water change will get this back on track
Phos 0
Nitrate 5ppm - big reduction on the 20ppm+ it was a while ago
Overall everything looks great, no complaints at all.