Unfortunately today was a different story. 500umoles was a bit much so I raised the fixture back to 24" and am at 400umoles canopy. Still at 150W, so four inches makes a big difference.
I hardly want to upload this picture from today- mostly because I know what's going on now.
It was also watering day, so some of the appearance can be attributed to that (but not much). I also fed nutrients for the first time, a 1/4 dose FoxFarms Big Bloom 0-.5-.7 soaked the pot until runoff not quite 10%. Let's see what tomorrow brings.
Pic is after feeding, yes the soil is supposed to look wet right now. I'm not overwatering.