Spotting leaves

[C7irca]

Help! This is my first grow. I'm about 2.5 weeks in on my oldest one and I've noticed spots that look as if they're burning thru the leaves on two of my three plants. It seems as if it started on older foliage. Idk what info is helpful aside from a pic so just some general info: I'm using a 600w led light, it's a dwc setup, gen hydro nutrients and cal mag, rock wood medium. Been between 75-80 with about 40% humidity.

Thanks!!!

 

[C7irca]

Re: Need some experienced help.

I've done some research and from what I've seen it may be calcium deficiency or maybe leaf septoria? ive added some more cal mag to my bucket about 24 hours ago, but doesn't seem to be halting the progression of leaf decay.

 

[Suntana]

That's definitely Calcium and slight signs of mag, in my experience it will continue to get worse then stop, but they won't fix the damage already caused. New growth should start improving soon.

 

[C7irca]

Awesome, thank you for the help! I had a suspicion it was calcium after reading online, but wanted to be sure.