problem with leaves dying.... fungus or nuteS??

i can't seem to figure out what is taking these leaves away. I am using a new room setup and used a new soil mix (normally used all Royal Gold Basement Mix, but got stuck using half RGBM and coco ProMix. I dont think it's a fungus. I sprayed with Serenade in the beginning and sprayed again last week. I also sprayed with Azamax twice so I dont think it's pests and I dont see any. I did have some spotting on my leaves which has cleared up pretty well since I did a flush with 5.8. -- Pic2

Could it be the mix ? not enough calcium? The curling dry grey leaves seems to be happening with the lower leaves. the spotting of leaves was happening all over - new and old growth.

any suggestions?? i'm going to put into flower in the next few days.

They need Phosphorus. Here's an example of a P-deficient leaf during veg:

View attachment 1405385

im pretty sure is nuit burn, tell me a) what kinda nuits b) ph balance? c) tbs per gallon if using nuits, and show me a pic of the entire plant if you can

oh and how often you feed

That is certainly not nutrient burn. It's P deficiency.