Wurlz F1 Automatic

*Tapwater: 21,3 °dh, 7.7 Ph, ec 700 Osmosis 23°, Ph 5,8, ec 500 switching to osmose only, adding additional Cal + Mag planned keeping light at 50% (400-500 ppfd), i fear more light will worsen the deficiency until i buy calmag (biobizz calmag 1ml = 33mg Calcium, 11mg Magnesium) 0.5 m distance i suspect Cal+mag def due to lack of transpiration caused by LED or too much kali? Lumatek would suggest 100% and 0,5 m distance at this point