What are these white marks on my leaves? Are they bad?

Not sure how these came to be, I give them a pre heavily diluted nute solution via leaves but i dont think this would be the case. Any ideas?

salt build-up drying on the leaf surface. just spray them down with water.

Yeah try pure water. maybe even try to whip it off if your not using purified water.

Hey,,i may be wrong but i dont think that is residue, mainly as i dont see it on the leaf above, or around,, also there is water on those leaves, which would smear those lines,, they also look like squiggly line,,not residue,, looks similar to leaf miner damage, i could be wrong its just that it dosnt look to much like residue,, my eyes maybe shit though,,
so op,, is it on other leaves or just this one?
Just my thoughts,, look at other leaves and see to compare,,,