I think I added too much Mg. first they started to look better and then worse. big leaves are quite dark and curling down with some lower leaves still yellowing, some of the roots looked with not much root system and off white maybe from nute burn.
2 days ago I dumped the nute solution, sterilized the tank with H2O2 and flushed the plants with a solution of H2o2 ran the system on/off till the folowing morning. The next morning I dumped the res EC.0.6 filled the tank with water EC. 0.1 and ran the system as normal. This morning the plants looked healthier some leaves even have a healthy shine I checked EC 0.4 will keep it with same water till tomorrow. If the EC is the same in the morning and depending how the plants look I'll add my General Hydro nutes at 1/4 strength and see how I go from there. This morning I flushed the mother plants with water as they also looked over nuted with leaves curling down. Already they Sprayed all plants and soaked rock wool with water and rizotonic 4ml/L.
did'nt put any pics. embaresed

Next time I add ca or mg I will measure the start water in this case EC. 0.1 and add ca & mg until The EC is between 0.3 & 0.4
which I believe to be the EC of softish tap water. I believe this is much beter than even going by manufactures Nute recomendations even at half doses.

Not too sure if I should add equal parts of Ca & Mg.
I was thinking to add 2 parts Ca to 1 part Mg as i believe generally there is more Ca than Mg in good tap water but would like your input on this.

Thanks in advance