Mix your nutrient solution as always and monitor its pH for next 24hr. Just let it sit and take measurement after 12hrs and than after 24hrs. You should see it drifting back to some point thanks to the water buffer capacity. Your nutrients already have enough calcium, it means your “deficiency” is not because you have not provided calcium, but it can be antagonized by to much K from your pH up or by other culprit like to much calcium (even if it is not in exchangable or soluble form) in your tap plus calcium in your base plus calcium from calmag plus calcium in your medium as dolomite lime and than shitload of pH up. That leads me to suggest skipping calmag as well as pHing to 6,3. If it not drifts back above 6,0 after one day sit, than adjust it to 5,8-6,2 and feed. When go plain forget about pH. At the end I would like to mention, that you need time to see improvement, doing so much things in short period of time gives you nothing to the future since you wont be able determine which one actually worked for you.