What am I facing? Plant is getting worst everyday, and I can't find the reason why. Thought it was a calmag def, but now I don't really now.

You might be over doing it with your plants on the feed. I forget whether it's P or K but it's something like...A potassium toxicity will show up as a Mg deficiency. So you when you added the extra calmag without flushing first it probably made it worse. You've done the right thing with the flush. I'd start at 1/4 strength nutes and work your way back up. I don't know much about those kinda nutes but 11.65ml/l seems crazy high. I'm at 10 but half of my feed is pure calcium and it gets eaten up in half a day which leaves my ppm average at 450. Anything over 800 is overkill imo.