Magnesium Deficiency??

I have a plant that looks like it has the Magnesium Deficiency problem! Im not sure if it is, can you guys tell me what it is and how to fix it!!
Shes in FFOFS with no nutrients yet, not sure if that helps.

Looks like you got it right, I'd say Mg too. I found out quickly that I needed to add calmag in FFOF with my white widows.

I'm not sure on what to get her, can you give me an idea on what to get?

I use calmag+ but thats the only one I've used. Any calmag supplement will work.

Thanks dude I'm going to get some, this is my first time having this problem