Some Brown spots

[Orgniv]

Hi guys, i'm fairly new to growing and i have a small plant that has started to get a Brown tip on one of the leaves.

Could this be too much nutes?
Heatstress?
Underwatering?
I'm using tap water with nutrients and the pH is around 6-7.3


I know you guys probably cringe over the aluminum foil sorry


Any help is greatly appreciated!

 

[pomass]

When I started having these on my plants I thought it was heat stress , but it turned out to be spider mites. Be watching for smaller spots to appear and then you can be sure. Most of the leafs affected on my plants were the lower fans at first. They had dried brown spots and just looked like I was needing to water but I knew it wasn't that as I water enough. then I started noticing speckled leaves higher up then I was sure. At the base of the plant you may notice some webbing.

 

[Orgniv]

Ill be sure to keep an eye, thanks!