Plant just grew second set of leaves but the bottom leaves(first set) have couple small brown spots and the top is vibrant medium green. What could this be, other plants in bubbleponic system are fine and the ph is 5.8
If it's the initial set of rounded seedling leaves that is totally normal. They will eventually brown off and fall off.
I'm no expert but I caused a brown spot by leaving some water on a leaf, then I think the light burns it n makes it go brown,