Yellowing Leaves with Purple and Brown Spots

Can someone PLEASE help me with my first grow? Everything was going great until a week ago. Some of the middle leaves started yellowing and gaining purple and brown spots. I am 4 weeks into veg from clones, getting ready to switch to flowering. See attached photos.

Setup:
2x4 tent
4x8 T5 fixture
6" fan/filter combo
Ebb and Flow system running 15 minutes 4 times a day during lights on (18/6)
4" rockwool cubes in hydroton
(2) 6" Circulation fans

Temp: ~75-80
pH: 5.6-6.0
Humidity: 35-50%
EC: 2.0 (when the problem started I was running an EC of 1.2. I thought maybe I had a P or K deficiency so I bumped the nutes)
Nutes: AN Grow A&B, Voodoo Juice, Cal-Mag

Did I miss anything? If so please let me know. I am desperate not to screw the pooch the first time around. Plus, chicks will dig it if you help me

Did a flush with FloraKleen and am running straight RO water. Woke up this morning and the tips of the new growth look yellow and maybe slightly burnt and the tips of many other leaves is curled down into a claw shape.

Any input is appreciated. Still not sure if I burnt the plants, or if I am dealing with a hungry plant, or something else.

Here is a current view from the tent cam.

that looks more as P deficiency but from a lock out rather unfed , back off a little on the nitrogen food ( lower ur overall ppm readings ) put less cal/mag and keep the P / K feed the same , ur plant is overfed not hungry , unnuted r/o water will not solve anything just lower the nutes amount for a while

Thanks for the input. I have put them on a light feeding schedule, and they seem to be de-clawing. Hopefully they are back on the mend.

Current view from the tent cam (there are three plants in there somewhere):