Sad brassicas... Help

Hello permie community. Tending to our starts this season with some great success (knocks on wood). Except these pesky brassicas! Am I looking at pest damage with those brown marks through the leaves? As well, does anyone think the variable green in the leaves is an early sign of low nitro? Our seedling mix is; potting mix, coco coir, vermicastings and "marl" which is basically a calcium rich rock dust. Our tomatoes and peppers are not showing the same condition so it's hard to dial in what's wrong. Any help would be fantastic!

Hi Mike, Is it just the first set of leaves that have the damage? Looks like the newer leaves are OK ?

How are you watering them, from the top or bottom, do leaves get wet?

From the top but the focus of the spray is the soil. The leaves do sometimes get wet. We have very hard water as well.