Yellow Mottling of leaves

Interesting to note, the green on the right side of the middle finger leaf is due it being underneath the the leaf to the right. I had added a dedicated UVB light to the grow.

I have seen this on my leaves now and again, whats the uvb light for? Did it cause this?

If you start to research increasing mj potency, you'll find that UVB stimulates THC production. I added dedicated reptile lights instead of switching out my HPS for MH.

As for did it cause this, my guess is that it did with some combination of not having a particular nutrient to protect from the UVB rays.