Yellow Veins Auto Cheese

Auto cheese Week 3 in DWCph 5.8PPM 340 (50 out of tap)H20 temp 68Amb air temp 73Humidity 35%400 watt MH 18/6 15" from canopyFirst grow first post, I've read the stickies, edges of fan leaves not veins are always mentioned. Just curious, it does not look to bad. Maybe just it's age, transition from seed to root feed? Lower my ppm maybe???Ohh sorry about no Pic, I have one but this manage attachments button does not seem to work, ??? Something I am doing wrong???I'm new, be gentle

Ok so this Noob learned to add a pic, first pic is of a week ago, second one of today. Changed out my nutes and brought them down to 150, added Cal Mag and they went to 200. The cal mag had Iron so I thought I would give it a whirl. Not sure if its a deficency or that the plant is just getting use to nutes. Maybe to soon to DWC?

Or are my lights to close and causing bleaching????

Anyone???? Please some help would be great, roots are still growing and plant is getting bigger. This is week 4, cut off the first set of true leaves as they yellowed and got brittle. The same thing is happening to new growth now. Only thing I have changed is bringing my nutes up to 600. This is the plant as of today. Would love some help....??????

Looks like the beginnings of a zinc deficiency to me.