My leaves are drying and cracking brown spots on most of the top leaves.
I have looked at your charts but what's the solution please I see it maybe the
Iron zinc mag and copper but any ideas how I can help my plants
What you describe sounds like a classic Ca-. Because it's an immobile element you're now really only going to be able to stop progression, not reverse the damage. They also do look burned. If you're using salt based fertilizers this is really easy to do and if you're not using very low EC feeds in between pushing full feedings, I think that can explain why you got the readings you did from the run-off.
I think a pH of 6.2 may be too high for rockwool cultivation, but I've never done RW so don't hold me to that. But, if I were in your place I'd be shooting for a full point lower here. I would also be using a Ca product as a foliar application instead of root feed. And I'd be flushing at about a .2-.3 EC. Again, since I've never done RW I'm not 100% positive on this, but I would treat it like coco coir in that you do
not flush with pure water, you use a mild nutrient solution or you're causing a huge shift in osmotic pressure in the root zone. That can cause problems, both immediately and further on down the road.
I would drop pH, drop EC without going to 0, and start giving MILD foliar feedings of Ca here. Then in the future, remember that the immobile elements really must be laid down from the get-go and feed accordingly from veg on.