what kind of nutrient deficiency? pics galore!

Hello there,

Can anyone tell me what kind of deficiency this is? It's happening to the fan leaves, from the bottom of the plant and making it's way up.
3 weeks old, 24/0
Hydro (DWC)
1000w HPS
Temps 20C (night) - 25C (day)

I thought it was a calcium deficiency. I checked the pH and it was high (6.1) so I corrected, that was three days ago. pH is down to 5.6ish and the problem is getting worse so I'm stumped.

I picked off a leaf and took a bunch of different pics, hope fully someone can help me out.

IMO they need at least 6 hours drk, but other than that I believe it is a Boron or manganese issue. Try a good micro after you flush.

From the "sick plant" guides, I thought that Boron and Manganese deficiencies showed up in newer growth first? My problem is showing up in mature fan leaves starting from the bottom and working it's way up the plant.