OK I couldn't get pictures but I was just checking out a grow under the BS 500. Two plants side by side one hydro/ rockwool slab, the other pro mix. The hydro is showing the same yellowing of the leaves that your seeing here. The one growing in dirt is a very healthy green. There are literally two stalks one from each plant side by side one yellowing the other not. BS is 15" above canopy. Hard to figure