Nutrient lockout?

[Growbig420420]

My girls are 3 weeks and 3 days since sprout. They have been looking quite pale these past couple days, but this morning I noticed one of the plants has developed dark marks on it. The other plants look somewhat green in the middle of their leaves but then look pale on their tips. Please take a look and see what you think. I will post my feeding schedule in the comments. Thanks

 

[Growbig420420]

Feeding schedule:
Canna coco a+b (8ml of each in 2L of water)
Canna Cal-Mag (2ml added with the a+b)
Daily feeding
I use 2L over all 6 plants

They are in 5 gallon pots so I feel like this may have something to do with it maybe? As 2L across the 6 plants doesn't give substantial runoff, it gives very very minimal runoff at the most

 

[Growbig420420]

Oh and the reason that last plant looks the way it does is that I fell asleep with the light on all night (I was very baked, and I usually run 18/6) and when I woke up it was really humid and there were water droplets on every single tip of the leaves

 

[Growbig420420]

Feeding schedule:
Canna coco a+b (8ml of each in 2L of water)
Canna Cal-Mag (2ml added with the a+b)
Daily feeding
I use 2L over all 6 plants

They are in 5 gallon pots so I feel like this may have something to do with it maybe? As 2L across the 6 plants doesn't give substantial runoff, it gives very very minimal runoff at the most

That is full strength as it directs on the bottles. I'm wondering if I should have been doing half strength

 

[trambles]

What is your water source? Well, city, etc?