Hey, long time no see 
I’ve started growing white widow autos and royal ak autos this year, they are in fourth week now. I’ve started noticing some problems with leaves, first some kind of brighter spots, though I’ve seen this last year and I think it was only genetics… But then they started to turn a bit brighter in the middle of the leaves - between the veins and the inner side closer to the veins a bit more darker and metal like ? (seen especially under the lights - it’s hard to capture in foto). Then some turned even yellow a bit (foto). And a few days ago the tips of the leaves (mainly the new ones) turned yellow-white ish.
I am using a 150W LED light (Viparspectra V300), about 55-60cm away - recommended (20/4 schedule). I have planted them into plagron lightmix (nutrients for one week) and I’ve watered them only few times with extra nutrients (plagrom terra grow half of the normal dose) after 10 days I’ve seeded them there - I’ve feared they would be burned. 9 days later I’ve repotted them (from 1,65) into 11L textile pots with the same lightmix soil and didn’t fertilized since.
I don’t think it’s a pH problem (been watering around 6 mostly, sometimes 8 tho), nor pests. I am thinking either light, although that seems improbable since they aren’t that close, or a nutrient problem. But I am not sure whether deficiency or abundance. Maybe N/P/Mg/K deficiency? I am really not sure, does anybody know? Would appreciate some advice 
First two pics are varigation nothing u can do but grow them out not a big issue, tips burned is likely a vpd issue or from a spray, the twist on leaves tells me ur magnesium is not on par with calcium ratios or is unavailable, could be from soil ph issues.a feed at 8 is way too high for any mix. Be great if u had a soil ph meter to know for sure slurry tests suck bad , some would argue but when u test both methods side by side the soil probe will tell a different story. If ph is high use apple cider vinegar to lower
U may also be over watering or have too much n in your pots leaves look droopy (could also be cold soil)
Hoppie’s got ya covered. 
Maybe in future just take ur pics with natural light. The blurple makes it hard to see the true colours of the leaf.
there u go oldguy thats some top notch advice. Who can see anything
Unfortunately I do not have soil pH meter, the water is around 7-8, but I haven’t watered them much, because the soil have been wet (never had such a problem with it). - next time it will be 6-6,5.
Nevertheless I did wait till the soil was dry now and than watered it.
I am moving them outdoors to sun. Fair point @oldguy, I am sending some more natural fotos below.
@hoppiefrog the tips are from vapor you say, if I understand correctly? But I haven’t used vapor for a few days and they have been outdoors the last couple of days. And new leaves are still turning yellow-white from the tips, so it can’t be that, right. I hope the terra grow fertilizer will fix the problem then. Couldn’t the tips be from malnutrient? Should I be worry?
And thank you all for help!
I believe @hoppiefrog is talking about VPD (search the subject with magnifying glass in top banner)
I believe you really need to know where you’re at on pH first. I would address that issue first before I worried about changing/adding nutes. Others will chime in, but you want to get the pH of your drain water down to 6.3-6.5 ish as quickly as possible. If you’re going to be a successful grower you are going to need a good pH and EC meter and learn how to use them…good luck!
EC meter only works on salts but otherwise I agree 100%
Ye I’ve got it now thanks. Then it probably is VPD issue, because they have been in very high humidity in a tent indoors (75-85%) so that’s problably the problem, right? But they are outdoors so that should fix it.
And it actually is a matter of nutruients, because when I add them into the water from a tap it drops to 6,5. They need to be fertilized now anyway so I wont use any higher pH than that anymore. I have a pH meter, though I havent tested drained water, will do that too, is that a good way to test the soil pH?
Thanx