Well im on my 2nd turn.. and the first one went very well until mid flower when i started showing the same issues you will see in the pictures. I am about to switch these to 12/12 but I am having trouble getting them healthy. Medium: 75% coco 25% perlite Nutrients: cns17 + Silica + Cal/MAg Lights: 2k watt over 8 plants Strains: Chem and Headband Plants age/size: 2 months/2 sq feet with many tops Container size: 7 and 10 gal Ventilation: 500 cfm Temp: 70-77 Humidity: 38% (Low but a few months ago when i seen these problems it was 65%) Feeding: Feeding 1.3 EC for the last 2 feedings, I water once my pots are light. every other day now. I have a very airy mix so I dont believe its an overwatering issue as i have let them dry out over the last week I do feed with every feeding (Your suppose to with coco) and I do believe I was over feeding for a few (like 1.5-1.7). This is what I thought the issue was the last run because it took a while to flush and get a low EC. With that being said you will see the plants have rigid edges like they are heat stressed and are dry to the touch. Now I dont have heat issues and I dont believe the humidity would be causing these issues.. So my conclusion was over feeding but after doing a few wet/dry cycles and feeding at 400ppm (250 is tap water + Cal/mag) the problem doesnt seem to be correcting itself. Its been about a week and I really need to go into flower now. Any suggestions? I know your not suppose to flush coco the same way as soil but if others also think its an overfeeding problem I may flush with ph water + clearex. Then follow with a low dose feeding. The big fan leaves are dry and rough and the leaves near the top are curled under (kind of like a n toxicity) and the brand new growth is folded in like a flower opening up. I appreciate any input. I was stumped by this last run and apparently this run also. Also forgot to mention I have pruple stems a lot fo supplementing cal/mag and for some reason my partner hit them last week with a low dose of bush load which is a growth regulator (he thought we were going to switch to 12/12 and use that again to limit the stretch. So I suppose that could be an issue too idk thats out of my league happy toking peacepipe