Light Burn? Mars Hydro TS3000 at 30% Power, 26 inches away per manual. I have since raised back to 30 inches.

Just had a similar issue, some people said cal mag deficiency, but I think I had over watered, similar random tiny yellow spots. I let my pots dry out for few days, then watered (yes, thanks uk420 and others, added a shot of cal mag) they went in to the next node with no other issues or spots etc, however the leaves that had been affected did retain the marks but they’ll get defoliate did they don’t fall off) I’m fairly new here, I grow in soil as it can act like a buffer and give you time to correct it (I’d like to try hydro, but not yet..) also it comes with quite a few of its own nutrients, especially good quality organic) Happy grow!