HelpfulGardener.com

I have a pepper plant I'm trying to grow hydroponically (for the first time).
I grew it from last year's seeds, and those plants were really successful (in soil).
Today I noticed these black spots on the older leaves and cotyledons, with some curling. The newer leaves seem ok at the moment (see pictures).

What can be causing this? Is this something I should worry about? My other pepper plants from the same seeds are outside in soil and don't have these black spots.

A lot of folks would say its a deficiency, some will say its normal especially in some hots and some will say its lighting.
I would lean towards the lighting group, Just keep an eye on it, I think it looks healthy, other than a bit of leaf curl on that one leaf.
I had a few on my sweets and after a while it went away but that was after it was transplanted, your in a different situation as you are growing in hydroponics.

The reason I am leaning towards lighting is because of the following picture;
The plants on left are under 6500k Led Tubes, plants on right are under Viparspectra 700's

ok, interesting. I will wait. Thanks for the tip!
(if it is a question of nutrients, I would be happy to know which ones it can be... I have access to all possible fertilizers, essentially )