Help fan leaves yellowing and falling

[ohme]

My plant is having trouble with fan leaves since I switched to 12/12 What is my problem? new leaves coming in are green but are curling under and die off too. I had gnats but that problem is resolved. I'm growing in promix, coco and perlite added to soil. LED is 450w and Is 24 inches above top of plant. I'll attach pic as soon as I figure out how to do that. I'm having problems with uploading pics.

 

[ohme]

I figured it out. Now as you can see the fan leaves are almost gone with new smaller leaves coming in. There is also some red/purple branches.and leaf stems. One more thing does this look normal? The dark green leaves have a skunky smell to them and the strain is super skunk. and this is my first grow and a learning curve. Thanks you in advance.