Well I have something bizzarre going on. I mentioned last page that I also have suddenly yellowing leaves. After making that post and reading for 20 min, I went back in and they were all droopy - looked like death. Now understand this is the same strain I always grow, same nutes, same process same everything, but I've never seen anything like this. So I go to the hydro store to get some foliar iron spray and when I get home, they look much better. No more drooping and unless my eyes deceive me, less yellowing.
I may never know what did this but now I'm wondering if those with the yellow top leaves (3.5 of 6) will ever recover and produce? The hydro shop guy says he doubts it. As I was driving home I thought, ditch the whole grow and start over. Now that I see some improvement, I don't know what to do.