Rust fungus or...?

Hey guys I’ve been giving my girls ample amounts of CalMag, so I wanted to confirm that this may be that rust fungus that I’ve read about? Any tips would be appreciated thank you!

Does it rub off?
Are you using 5ml/gal or whatever max suggested is with your cal/mag?

Also PH to make sure you’re in range to take it up?

It does not rub off. I realized I only put in half the calmag needed oops

What’s your solution EC?

Maybe someone else will recognize it as something else, the light doesn’t show much of a rusty color but when I took a pic of the deficiency to ask here it didn’t on my phone either.
But if not at least 1/2 cal/mag every feeding to maybe max every other (depending on what nutes I was using) I had same issue going into flower.

In hydro depending on the intensity of your light being used it will show deficiencies very quickly. Up dosage of cal/mag and keep an eye on new growth.

Those spots will never go away as the damage has been done

@KeystoneCops and @consciousk ask valid questions what are your Ec and ph?

If your ph isn’t in correct range you won’t uptake needed nutrients and first signs are cal/mag

Most of the time I have had a issue it has been a ph issue . My first grow I didn’t know you needed to adjust ph after your nutrients so my ph was always low luckily it was white widow and still did okay as they are the most forgiving to grow.
Also I didn’t know what EC was and people warned me about fox farms burning my plants so I never got over half strength on nutes until someone told EC was the same thing as PPM I actually had a ppm meter and didn’t know thats what it was . Had no idea how hard it is to grow a weed .