Leaf Edges turned upwards, heat stress indicated but temps are good.

[daihashi]

Only thing I can think of is.

+Neuts lock up
+unBalanced pH stressing your leaves

Don't use tap water!!!! Go out to the store and buy some distilled water. Or try Zypherhills. Watering could be your major problem I missed that your using tap water.

I'll go fill up some jugs today with distilled. Would it be a good idea to go ahead and run a flush?