Thank you for taking the time to explain that to me. The non-serrated leaves and nitrogen toxicity symptoms didn't catch my eye. But, that will give me an idea of what to look out for.
They look a lot like these Red Spider Mites to me. Do you have the damaged leaves, yet?
https://www.santyerbasi.com/en/blog/identify-and-kill-red-spider-mites/
Ah, okay I understand. That's too bad you're having issues uploading. Maybe if you're trying the Desktop site, you could try the Mobile one or vise-versa.
This looks kind of like nutrient burn to me. What were you feeding them at the time? I know it's been a while. But, could you please provide an update? I am wondering how things turned out.
I had the same cupping trouble with a Pineapple Express seedling recently. It was in soil and drowned to death. I get yours is in a different medium though. I personally don't have much co-co know-how. I am curious though - did your seedling survive?
I'm not sure if 100% of 450 Watts at 13 inches is too much necessarily for your plant's stage. I might try it with my light, but that's a 300 Watt TSW 2000. The reason I brought it up is because the leaf you showed seemed a little bleachy and crispy to me. Maybe it would help people diagnose...
I had some really airy bud recently that wasn't grinding well in the Kozo. So, I put the material in one of those plug-in coffee grinders. I wanted a kief-like powder, and it delivered. I might have been smoking stems, but I'd never know.
Hello, I apologize I did not realize you replied to my comment a while back. The grow light glasses I was talking about might have been able to accommodate glasses underneath. But, they are meant for blurples not HPS lights. I hope you might have found something by now that fits your needs.