It looks like nute burn to me, but 86F is pretty hot. What are your res temps? Seems early for P deficiency. When do you think your TDS meter will arrive? Also, foliar spraying with the lights on will cause hot spots on the leaves.
I am currently growing in recirculating DWC buckets. I will be expanding into an under current set up soon. I have pictures posted in my gallery if you want to see my plants. I also have a thread posted under the hydroponics section with current pictures. I didn't want to start my next grow...
Not sure why you were posting for immediate help if you already had your answers.
I have researched the Lucas formula and found that the plants usually show some type of deficiency. I think of the Lucas formula as a bare minimum on a budget feeding schedule.
Good luck with your grow.
Pictures would help. What did the roots look like before you transplanted them into hydroton? I also think you are using way too much nutes for a seedling. You should only be adding the nutes once a week then increase depending on how much your plant is growing. The plant will tell you if she is...