Hi wardrobe
I grew that same strain a while back, hydroponically, and had the same fan leaf color change. I added a little liquid karma [for trace elements] it helped a little. The flowering time was 50 days on the seeds i got, so you have a while for them to fatten up. The last 3 weeks they really got fat. I clipped off the dying fan leafs on mine, new ones replaced them. Has anything stressed them? power outage? cold or over heated?
excellent grow for a first timer, better than alot of us I bet.
peace
heart
ps. i use 1/2 teaspoon of ebson salts per gallon of water , you'll have to do the conversion lol.