Yes I don't understand this also today I dropped my ph 5.7 in hopes that it would help.
But I'm using T5 6500k for lighting because I'm vegging and using expanded clay.
Water is about 2 inches below net pot water temp about 65 deg. Here is a few more photos.
From what I figure is calcium deficiency but with that I can't figure out why...
Even new leaves are spotted with brown rust spots and getting worse as it gets older.
Ph 6.0 with checked calabration
Using foxfarm cal mag as directed 5ml per gallon
50/50 Ro /tap water
Roots look healthy...