[Help] Spots On Leaves

I've been looking around and I can't work out whats wrong with these leaves. Any help would be awesome.

They're like 6 weeks old, growing under a 120watt LED grow light in soil. Watering every couple of days from bottom and the strain is C-99. No other problems up until now and the others are doing fine.

Heres some pics:

It's likely calcium/magnesium deficiency, but also get them regular all around nutes as well if you haven't been doing that.

So would you say it's a calcium deficiency?

Can't say with 100% certainty, but giving it a little cal/mag (easily found anywhere for tomato plants) can't hurt it.

Ok thanks, I've been giving it tomato fertilizer so far but theres no cal in them so will give it a shot

Let me know if they get better.