I dont know those nutrients but it sure looks like your girl is hungry...I wld guess you need to feed more often or at a higher concentration. Jmo
Are you checking the ph of the water and nutrients that you use to water and feed with? Ph for soil needs to be maintained at 6.3-6.8 (6.5 is where I stay at) unless you are growing organically.
I agree with puffin early in flower I go to the lucas formula cutting most of the nitrogen. This grow about a week into flower I started noticine yellow new growth just like what you have. I hit em with a small dose of grow and in a couple days they were back green and lush.
I read that swinging temperatures from warm to cold can cause that. Having warm(75*f+) during the day and then cooling down to less than 60*f at night is what the information said would cause yellowing at the tops of the plants.
I have some plants that look very similar to yours and I have had some issues with them being in the low to mid 70*f and then during regular night when it gets cold here, their temps fall into the low to mid 50s. I have added extra lighting and closed up their growing area against the cold and now their tems stay in the mid 70s for the past week. Since they are still in veg, I am keeping the lights on constantly which should maintain the temps. I should see some changes in another week if the temps swings are the problem.
Are you maintaining steady temps within your grow area?
Yeah being in a 1meter tent with a 600w down close could be adding to that. Always make sure that the light is at the proper distance by placing your hand (palm down) over the highest point of the plant and hold it for 10 seconds. If the heat of the light starts getting uncomfortable to your hand then it is uncomfortable to the plant. raise the light about 12cm and see how it feels then.
If the light is too close and intense it could cause heat stress, leaf bleaching, or the wide temp swing from very warm under the light to very chilly in the dark time. You will have to test it out a bit until you find the answer.