Help!

Hi guys!
Today I noticed that to one of my NL auto plants have appeared brown leaf tips.
Some information: plant is about 3 weeks old, using cfl lighting, temperature is about 80F/26C, using DWC system.
If you need any other information, just ask.
Btw this is my 1st time grow.
Thanks.

i have never seen this before, it looks like it are really the tips, also the small ones, most of the time its really just the tip not the side tips too, are you sure its getting enough lighting and nutrients? what CFL's are you using?

PH problem.

Deep green w/ tips starting to brown/// Back off the nutes a little bit & you should be fine.

Light is ok 8x42w 6400k cfls for 4 plants, but I think that its calcium deficiency, at least here are the best pics that are similar to my problem: https://www.rollitup.org/marijuana-plant-problems/488004-guide-nutrient-deficiency-toxicity.html

hows the grow going? was it a calcium deficiency?