It's the edges of the leaves curling up, that made me think heat stress. I wish I knew more of Hydro stuff to help. I've seen people put the metallic tape on the lids. 82 is fine for a temp. But remember Metal Halide or Ceramic Metal Halide have UV-B in their spectrum which has more radiant heat. That's the lids being 91, so I'd raise it a few inches, & cut off the Cfl's.
By snake oil research, I mean Advanced Nutrient claiming un-proven numbers. Ingredients are trade secrets, analysis is un-verified. The prices they charge are insane. This all with research in Eastern Europe, then marketed with labels with women & big boobs. Plus some of that shit is 0-0-1 as a N-P-K for tons of $$.
It's a rip off to me & know none of their #'s and combos for their use.
But I'm a former landscaper, so soil grower. I just hate to see guys wasting money when products for stuff can be cheaper. Hope that helps, and explained what I meant.
Daniels