New Grow(2x cob cxm32) leaf spots

Hello, im New to Led Grow. This one im using a fixture with 2 cxm32 running low.
Growing media os coco, nuts from canna.
First days everything looking nice, one week pass and leaves are getting some spots.
Im wondering if anyone can help.
Thank you

Too big of pots for such small plants...especially in coco. These should be in solo cups so they can be fed every day. The little plants and giant pots will make watering daily difficult...and watering daily is what you're after. At this point be sure you buffered your coco, be sure you're always giving them feed (no plain water) and be sure not to let the coco dry out. Good luck.

Im going for 12/12 from the begining, sog, so i put them in final pots. Coco was buffered, and feed them everyday.
Im thinking it was from me lowering the light a bit. I raised it next Day and New growth seems fine.
Its not burn from heat, i think it was from lightbleach.
Wainting to see.
Regards