Question about what I think is a PH issue at 6 weeks into flower.

Well I have a couple plants, fairly quickly flowering indicas, that are 5.5 to 6 weeks into flowering and i'm planning to cut them down in about 2 weeks, 3 more at the most. They seem to be having issues with PH and have for about a week or so now. All of the fan leaves are starting to turn yellow and die except maybe the top 3ish sets (Plants are about 3 feet tall) and they show sign of being deficient in most other minerals, not too bad but starting to have an effect on the lower leaves. This is certainly not due to underfeeding though, they get some of the Nectar of the Gods stuff + a cal/mag supplement at 1/2 strength at every feeding plus I put them in super wicked expensive organic soil the hydro store guy reccomended. What it looks like is the natural yellowing of the plant in mid to late flower added into the mix with some issues with the PH. My question though; is it worth trying to correct this at this point being that they only have 2 or 3 weeks left, i'm more afraid of killing them in the process of fixing it than I am of them dieing from being a bit short on nutrition.

Id take some pics but I don't have a camera that is any good. Basically the fan leaves are very yellowed on the bottom half of the plant, some are dieing, top half is better, only starting to slightly yellow in the centers and not really too bad. About half the fan leaves on the plants and maybe like 5-10% of the sugar leaves have some little dead spots in them from what looks like K def and there are some which are starting to gray and dry out looking like a P def. Basically you can tell they arent 100% but they dont look like they are about to keel over dead imminently or anything.

What would be my best course of action being that i'm so close to harvest?

Hmmm at this stage i would just flush then use plain water sense you are so close to harvest.

Is that an Ear? Kinda looks like a nostril?..... 0.o