Yellow fan leaves week 8

well, you got a ton of leaves so a few dying is no big deal, but hints at an underlying issue - nutes, pH, ec etc... Looks to be a mobile nutrient, since it's cannibalizing itself from bottom-up instead of where the most light is hitting. yellowing from tip -in.. and curling at bottom/older leaves. Looks liek N-def... don't see any spots beside the one in pic 2 and could just be a blemish ro something else. this could be normal.. could stick to your current schedule and see if plant is just shedding a few leaves, but i think it just needs a bit more N... or rais pH slightly if you think the concentrations and ratios of what you feed are proper already. raising pH a bit will help with availablility of N in the plant.

It's simply down to lack of nitrogen and lack of light. The lower leaves are not getting any light so they will die off first. But slightly higher up you can see a defeciency in nitrogen. You could also do a light defoliation to remove some of the largest fan leaves and the unhealthy ones 👍🌱