With my cocktail for 2nd lady I reach an EC of 580...

Hello ! At that stage in soilless medium you should already be around 1.5 / 1.7 Ec and the cal mag should represents 0.3 points of Ec which mean that with a tap water at 0.3 Ec you add cal mag until 0.6 is reached then you go to 1.5/1.7 by mixing your nutrients. So to answer your question : yes you need to add more nuts. And you can't do anything to make her gain more height as the stretch is now almost done so until harvest the gain of height will not be up to 5cm. I hope it will help you 😁👍