These are 2 flowering AFs. Day 26 day 13. I THINK it started about a week ago. Se. Lots of variables here. And the plant with all the issues has had a few. Light burn co² burn.. but this yellow at the vein that has shown up on a hand full of leaves on both plants. So im wondering if it's environmental. Since they're 2 weeks apart. The healthy one was still getting blood bud last feeding. The older one the domestic abuse plant. That hasn't had bud blood for almost 2 weeks. Now so feeding is different. My dehu wasn't hitting the target right so RH was down To 38% last 3 nights and I missed it wasn't watching.. in promix flx. 3 gal air pot Ro water Great white, advanced nutrients connoisseur, advanced b52 and calmag bud blood. Voodoo juice for the 1st 2 weeks of flower.. 800 watt led and 700 watt cmh which I rotate them between. PAR Is about 1100 right now with the low co2 levels. But will increase to 1400 incrementally once co2 goes up over 1000 depending on where they are. And co 2 is running on 1 hr Intervals with 5min air exchange currently at only 880ppm and going up 10ppm a day. My co2 burn happened 20 days ago. The air exchange wasn't set up right the first night. So it sat with the same co2 at somewhat high levels 1400 ish for 4 hrs. NL otherwise is healthy as an ox with a 16in top cola..!!