Need help!!...light green spots on bottom fan leaves..any advice greatly appreciated!!

[Renaissance Redneck]

All good, man! I thought spot burn would be it, but any time I see straight lines between margins I like to check the undersides for bugs. : A South Texas knee jerk!
Gals are really looking good!

Hey Renaissance Redneck,
Humidity is a solid enough 50-55 all the time. I know one of the pics says 67 on the meter but tat because i had it outside of the grow closet. Thanks for your reply i have inspected both top and bottom of the leaves and cant see anything wrong. I'm leaning towards it being nute burn from splashes of water when i was feeding them. It doesn't seem to have gotten any worse and is just on the same leaves not on any of the newer leaves. Will post some pics shortly. Thanks again.