Brown spots, yellowing leaves, pests?

Looks like a calcium deficiency with your overall yellowing and brown spots Are you growing coco ? What is your ph and EC levels ? I’ll check the run off and correct if your ec is to high you might be locking out nutrients. Best of luck to you.

Thanks for your answer 8thChevron. Definitely not pH, have a digital probe recently calibrated, and not water / magnify issue on leaf. I found a couple gnats earlier so thinking the infestation is larger than thought. Treating with H2O2 1:4 flush and topsoil sand to prevent any new ones. Has anyone had issues with gnats and any recovery issues?

Because it looks like you have 3 or 4 different nutrient issues going on, I would be willing to bet that your pH is off. Either in your feed or runoff, the runoff I'm guessing is below 5. Check pH, flush if necessary, then reset. The brown spot on the first picture could be gnats and fungus, but it looks to me like the leaves got wet and then got hit with some strong sunlight.